Image forming apparatus developing unit and computer system

ABSTRACT

An image forming apparatus, for example, that is capable of accurately writing information into a developing unit or the like having an element is achieved. An image forming apparatus comprises: an attach/detach section to and from which a developing unit having an element into which information can be written and a developer containing section can be attached and detached; a photoconductor on which a latent image can be formed; a writing member for writing information into the element; and an AC voltage supply section for supplying an AC voltage. During a period from a start to an end of an image forming process, the writing member writes information into the element of the developing unit attached to the attach/detach section when the AC voltage supply section is not supplying an AC voltage.

TECHNICAL FIELD

The present invention relates to image forming apparatuses, developingunits that can be attached to and detached from an image formingapparatus unit, and computer systems provided with a computer unit andan image forming apparatus.

BACKGROUND ART

Among image forming apparatuses such as laser beam printers, there arethose in which a developing unit provided with a memory can be attachedto and detached from the image forming apparatus unit. In such imageforming apparatuses, information is written into and read from anelement provided on the developing unit.

There are also image forming apparatuses that have AC voltage supplysections. In such image forming apparatuses, an AC voltage is suppliedfrom the AC voltage supply section to, for example, the developingdevice or the charging device, and this AC voltage is used fordeveloping latent images or charging the photoconductor.

However, it is necessary that information is accurately written into andread from the memory. For example, when writing information about theremaining amount of toner into the memory provided on the developingunit, if incorrect information is written, then the amount of tonerremaining in the developing unit cannot be managed properly.

The present invention has been made in view of the foregoing problem,and it is an object thereof to achieve image forming apparatuses andcomputer systems with which information can be accurately written intodeveloping units having elements, for example.

It is a further object of the present invention to achieve developingunits, image forming apparatuses, and computer systems with whichcommunication with an element can be carried out accurately.

DISCLOSURE OF INVENTION

A main aspect of the present invention is an image forming apparatuscomprising: an attach/detach section to and from which a developing unithaving an element into which information can be written and a developercontaining section can be attached and detached; a photoconductor onwhich a latent image can be formed; a writing member for writinginformation into the element; and an AC voltage supply section forsupplying an AC voltage, wherein, during a period from a start to an endof an image forming process, the writing member writes information intothe element of the developing unit attached to the attach/detach sectionwhen the AC voltage supply section is not supplying an AC voltage.

Further, another main aspect of the present invention is an imageforming apparatus comprising: a photoconductor unit attach/detachsection to and from which a photoconductor unit having an element intowhich information can be written and a photoconductor can be attachedand detached; a developing device for developing a latent image formedon the photoconductor; a writing member for writing information into theelement; and an AC voltage supply section for supplying an AC voltage,wherein, during a period from a start to an end of an image formingprocess, the writing member writes information into the element of thephotoconductor unit attached to the photoconductor unit attach/detachsection when the AC voltage supply section is not supplying an ACvoltage.

Further, another main aspect of the present invention is a developingunit comprising: a developer bearing body including a rotating shaft anda large diameter section that has a diameter larger than a diameter ofthe rotating shaft and that is for bearing developer, wherein thedeveloper bearing body is capable of rotating about the rotating shaft;an element with which communication is possible; and a developercontaining section for containing developer, wherein the element isprovided more to the outside than the large diameter section in an axialdirection of the rotating shaft.

Further, another main aspect of the present invention is an imageforming apparatus comprising: a developing unit including a developerbearing body including a rotating shaft and a large diameter sectionthat has a diameter larger than a diameter of the rotating shaft andthat is for bearing developer, wherein the developer bearing body iscapable of rotating about the rotating shaft, an element with whichcommunication is possible, and a developer containing section forcontaining developer; an attach/detach section to and from which thedeveloping unit can be attached and detached; and an antenna forwirelessly communicating with the element of the developing unitattached to the attach/detach section, wherein the element is providedmore to the outside than the large diameter section in an axialdirection of the rotating shaft.

Features and objects of the present invention other than the above willbecome clear through the discussion of the present description and theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram for describing a configuration in which a developingunit 54 (51, 52, 53) and a photoconductor unit 75 are attached to anddetached from a printer unit 10 a.

FIG. 2 is a diagram showing main structural components that configure aprinter 10.

FIG. 3 is a block diagram showing a control unit 100 provided in theprinter 10.

FIG. 4 is a perspective view of a yellow developing unit 54 seen fromthe side of a developing roller 510.

FIG. 5 is a cross-sectional view showing main structural components ofthe yellow developing unit 54.

FIG. 6A is a plan perspective view showing the configuration of anelement.

FIG. 6B is a block diagram for describing an internal configuration ofthe element and a send/receive section.

FIG. 7 is a diagram for describing information stored in a memory cell54 h of the element 54 a.

FIG. 8 is a diagram for describing information stored in a memory cellof the element 54 a of the photoconductor unit 75.

FIG. 9A is a diagram for describing the relationship between the elementand the printer-side antenna when the yellow developing unit 54 ispositioned at the developing position.

FIG. 9B is a diagram for describing the relationship between the elementand the printer-side antenna when the yellow developing unit 54 ispositioned at the attach/detach position.

FIG. 9C is a diagram for describing the relationship between the elementand the printer-side antenna when a rotary 55 is positioned at the homeposition.

FIG. 10 is a flowchart for describing how information is written intothe elements of the developing units.

FIG. 11 is a flowchart showing an example of how information is writteninto the element 75 a of the photoconductor unit 75.

FIG. 12 is an explanatory diagram showing the external configuration ofa computer system.

FIG. 13 is a block diagram-showing the configuration of the computersystem shown in FIG. 12.

FIG. 14 is a perspective view of a yellow developing unit 2054 seen fromthe side of a developing roller 2510.

FIG. 15 is a cross-sectional view showing main structural components ofthe yellow developing unit 2054.

FIG. 16A is a diagram for describing the relationship between theelement and the printer-side antenna when the yellow developing unit2054 is positioned at the developing position.

FIG. 16B is a diagram for describing the relationship between theelement and the printer-side antenna when the yellow developing unit2054 is positioned at the attach/detach position.

FIG. 16C is a diagram for describing the relationship between theelement and the printer-side antenna when the rotary 55 is positioned atthe home position.

A legend of the main reference characters used in the drawings isdescribed below.

-   10 printer-   10 a printer unit-   10 b first open/close cover-   10 c second open/close cover-   10 d photoconductor unit attach/detach opening-   10 e developing unit attach/detach opening-   20 photoconductor-   30 charging unit-   40 exposing unit-   50 YMCK developing device-   51 cyan developing unit-   52 magenta developing unit-   53 black developing unit-   54 yellow developing unit-   51 a, 52 a, 53 a, 54 a elements-   54 b noncontact IC chip-   54 c resonant capacitor-   54 d antenna-   54 e rectifier-   54 f signal analysis section RF-   54 g controller-   54 h memory cell-   55 rotary-   55 a central shaft-   55 b, 55 c, 55 d, 55 e attach/detach sections-   60 first transferring unit-   70 intermediate transferring body-   75 photoconductor unit-   75 a element-   76 cleaning blade-   76 a waste toner containing section-   80 second transferring unit-   90 fusing unit-   92 paper supply tray-   94 paper supply roller-   95 display unit-   96 resist roller-   100 control unit-   101 main controller-   102 unit controller-   112 interface-   113 image memory-   120 CPU-   121 serial interface-   122 printer-side memory (storage element)-   123 send/receive circuit-   124 a printer-side antenna (for communicating with photoconductor    unit element)-   124 b printer-side antenna (for communicating with developing unit    elements)-   125 YMCK developing device drive control circuit-   126 a AC voltage supply section-   126 b DC voltage supply section-   127 exposing unit drive control circuit-   127 a pixel counter-   510 developing roller (developer bearing roller)-   520 seal member-   524 seal urging member-   522 seal support metal plate-   530 first toner containing section-   535 second toner containing section-   540 housing-   541 opening-   545 restriction wall-   550 toner supply roller (toner supplying member)-   560 restriction blade-   560 a rubber section-   560 b rubber support section-   562 blade support metal plate-   570 blade backing member-   1000 computer system-   1102 computer unit-   1104 display device-   1106 printer-   1108 input device-   1108A keyboard-   1108B mouse-   1110 reading device-   1110A flexible disk drive device-   1110B CR-ROM drive device-   1202 internal memory-   1204 hard disk drive unit-   T toner-   RS read sensor for synchronization-   2051 cyan developing unit-   2052 magenta developing unit-   2053 black developing unit-   2054 yellow developing unit-   2051 a, 2052 a, 2053 a, 2054 a elements-   2124 b printer-side antenna (for communicating with developing unit    elements)-   2510 developing roller (developer bearing roller)-   2512 rotating shaft-   2514 large diameter section-   2520 seal member-   2524 seal urging member-   2522 seal support metal plate-   2530 first toner containing section-   2535 second toner containing section-   2540 housing-   2541 opening-   2545 restriction wall-   2550 toner supply roller (toner supplying member)-   2560 restriction blade-   2560 a rubber section-   2560 b rubber support section-   2562 blade support metal plate-   2570 blade backing member

BEST MODE FOR CARRYING OUT THE INVENTION

At least the following matters will be made clear by the discussion inthe present description and the accompanying drawings.

An image forming apparatus comprises: an attach/detach section to andfrom which a developing unit having an element into which informationcan be written and a developer containing section can be attached anddetached; a photoconductor on which a latent image can be formed; awriting member for writing information into the element; and an ACvoltage supply section for supplying an AC voltage, wherein, during aperiod from a start to an end of an image forming process, the writingmember writes information into the element of the developing unitattached to the attach/detach section when the AC voltage supply sectionis not supplying an AC voltage.

If a developing unit, which has an element into which information can bewritten and a developer containing section, is configured so that it canbe attached to and detached from an attach/detach section, then there isa possibility that a developing unit attached to the attach/detachsection will become detached. Consequently, it is preferable thatinformation about the remaining amount etc. of developer that iscontained in the developing unit is suitably written into the element ofthat developing unit. On the other hand, if an AC voltage supply sectionfor supplying an AC voltage is provided, then when the AC voltage supplysection is supplying an AC voltage, there is a possibility thatelectromagnetic noise will be generated in the periphery of the ACvoltage supply section.

With the foregoing image forming apparatus, the writing member writesinformation into the element of the developing unit attached to theattach/detach section when the AC voltage supply section is notsupplying an AC voltage during the period from the start to the end ofan image forming process, and thus information can be written accuratelywithout being affected by noise caused by supplying the AC voltage, forexample.

Further, in this image forming apparatus, the developing unit may have adeveloper bearing body for bearing developer; and the AC voltage supplysection may supply an AC voltage to the developer bearing body.

With this image forming apparatus, the writing member writes informationinto the element of the developing unit attached to the attach/detachsection when the AC voltage supply section is not supplying an ACvoltage to the developer bearing body during the period from the startto the end of an image forming process, and thus information can bewritten accurately without being affected by noise caused by supplyingthe AC voltage to the developer bearing body, for example.

Further, in this image forming apparatus, the image forming apparatusmay comprise a charging member for charging the photoconductor; and theAC voltage supply section may supply an AC voltage to the chargingmember.

With this image forming apparatus, the writing member writes informationinto the element of the developing unit attached to the attach/detachsection when the AC voltage supply section is not supplying an ACvoltage to the charging member during the period from the start to theend of an image forming process, and thus information can be writtenaccurately without being affected by noise caused by supplying the ACvoltage to the charging member, for example.

Further, in this image forming apparatus, the image forming apparatusmay comprise a moving body provided with a plurality of theattach/detach sections, and an attach/detach opening through which thedeveloping unit is attached to and detached from the attach/detachsection; in a state in which the developing unit is positioned at anopposing position where the developing unit is in opposition to thephotoconductor due to movement of the moving body, the latent image maybe developed with the developer contained in the developing unit; in astate in which the developing unit is positioned at a detaching positionthat is different from the opposing position due to movement of themoving body, the developing unit may be detached from the attach/detachsection via the attach/detach opening; and during a period from when thedeveloping unit arrives at the opposing position until when thedeveloping unit arrives at the detaching position due to movement of themoving body, the writing member may write information into the elementof the developing unit.

If the image forming apparatus is provided with an attach/detach openingthrough which the developing unit is attached to and detached from theattach/detach section, then there is a possibility that a developingunit attached to the attach/detach section may carelessly be detachedvia the attach/detach opening. In particular, since the amount ofdeveloper in a developing unit decreases when the developing unit ispositioned at the opposing position and development is carried out, ifthe developing unit is detached before information about the amount ofdeveloper that has decreased is written into its element, then it maynot be possible to ascertain the amount of developer contained in thedeveloping unit, for example.

Here, with the foregoing image forming device, the writing member writesinformation, such as the remaining amount of developer, into the elementof the developing unit during a period from when the developing unitarrives at the opposing position until when the developing unit arrivesat the detaching position due to movement of the moving body, and thus,information, such as the amount of developer contained in the developingunit, is written accurately without being affected by noise caused bysupplying an AC voltage, for example, even if the developing unit isdetached via the attach/detach opening.

Further, in this image forming apparatus, during a period from when thedeveloper bearing body provided in the developing unit that has arrivedat the opposing position ends developing the latent image until when thedeveloping unit arrives at the detaching position, the writing membermay write information into the element of the developing unit.

The amount of developer in the developing unit decreases when the latentimage is developed by the developer bearing body provided in thedeveloping unit. Here, with the foregoing image forming apparatus, thewriting member writes information into the element of the developingunit during a period from when the developer bearing body provided inthe developing unit that has arrived at the opposing position endsdeveloping the latent image until when the developing unit arrives atthe detaching position. Consequently, information, such as the remainingamount based on the amount of developer that has decreased throughdevelopment, is written into the element of the developing unit.

Further, in this image forming apparatus, during a period from when thedeveloping unit starts moving from the opposing position until when thedeveloping unit arrives at the detaching position due to movement of themoving body, the writing member may write information into the elementof the developing unit.

With this image forming apparatus, information can be writteneffectively using the period of time from when the developing unitstarts moving from the opposing position until when the developing unitarrives at the detaching position due to movement of the moving body.

Further, in this image forming apparatus, if, during the period fromwhen the developing unit starts moving from the opposing position untilwhen the developing unit arrives at the detaching position, anotherdeveloping unit adjacent to the developing unit on the upstream sidetherefrom in a direction of movement of the moving body arrives at theopposing position, then the writing member may write information intothe element of the developing unit during a period until the otherdeveloping unit arrives at the opposing position.

With this image forming apparatus, the writing member writes informationinto the element of the developing unit during a period until the otherdeveloping unit arrives at the opposing position, and thus, informationwould already be written into the element, even if the developing unitis forcibly detached after the other developing unit has arrived at theopposing position, for example.

Further, in this image forming apparatus, a difference between a maximumvoltage value and a minimum voltage value of the AC voltage may be 1000volts or more.

When the difference between the maximum voltage value and the minimumvoltage value of the AC voltage is 1000 volts or more, theelectromagnetic noise that is generated also becomes large. With theforegoing image forming apparatus, the writing member writes informationinto the element of the developing unit attached to the attach/detachsection when the AC voltage supply section is not supplying an ACvoltage during the period from the start to the end of an image formingprocess, and thus information can be written accurately without beingaffected by the large noise caused by supplying the AC voltage, forexample.

Further, in this image forming apparatus, the writing member may writeinformation into the element in a non-contact state with respect to theelement.

If the writing member writes information into the element in anon-contact state, then there is greater susceptibility toelectromagnetic noise than in the case where the writing member writesinformation into the element in a state in which it contacts theelement. With the foregoing image forming apparatus, the writing memberwrites information into the element of the developing unit attached tothe attach/detach section when the AC voltage supply section is notsupplying an AC voltage during the period from the start to the end ofan image forming process, and thus information can be written accuratelyin a non-contact state without being affected by the large noise that iscaused by supplying the AC voltage, for example.

Further, in this image forming apparatus, the writing member may write,into the element, information indicating a remaining amount of developercontained in the developing unit provided with the element.

Since the developer contained in the developing unit decreases asdeveloping is carried out, it is preferable to appropriately write theremaining amount of developer into the element. Here, with this imageforming apparatus, information about the remaining amount can be writtenaccurately without being affected by the large noise caused by supplyingthe AC voltage, for example.

Further, in this image forming apparatus, the writing member may write,into the element, information indicating a usage amount of developercontained in the developing unit provided with the element.

Since the developer contained in the developing unit decreases asdeveloping is carried out, it is preferable to appropriately write theusage amount of developer into the element. Here, with this imageforming apparatus, information about the usage amount can be writtenaccurately without being affected by the large noise caused by supplyingthe AC voltage, for example.

It is also possible to achieve an image forming apparatus comprising: anattach/detach section to and from which a developing unit having anelement into which information can be written and a developer containingsection can be attached and detached; a photoconductor on which a latentimage can be formed; a writing member for writing information into theelement; and an AC voltage supply section for supplying an AC voltage,wherein: the developing unit has a developer bearing body for bearingdeveloper; the AC voltage supply section supplies an AC voltage to thedeveloper bearing body; during a period from a start to an end of animage forming process, the writing member writes information into theelement of the developing unit attached to the attach/detach sectionwhen the AC voltage supply section is not supplying an AC voltage to thedeveloper bearing body; the image forming apparatus comprises a movingbody provided with a plurality of the attach/detach sections, and anattach/detach opening through which the developing unit is attached toand detached from the attach/detach section; in a state in which thedeveloping unit is positioned at an opposing position where thedeveloping unit is in opposition to the photoconductor due to movementof the moving body, the latent image can be developed with the developercontained in the developing unit; in a state in which the developingunit is positioned at a detaching position that is different from theopposing position due to movement of the moving body, the developingunit can be detached from the attach/detach section via theattach/detach opening; during a period from when the developing unitstarts moving from the opposing position until when the developing unitarrives at the detaching position due to movement of the moving body,the writing member writes information into the element of the developingunit; if, during the period from when the developing unit starts movingfrom the opposing position until when the developing unit arrives at thedetaching position, another developing unit adjacent to the developingunit on the upstream side therefrom in a direction of movement of themoving body arrives at the opposing position, then the writing memberwrites information into the element of the developing unit during aperiod until the other developing unit arrives at the opposing position;a difference between a maximum voltage value and a minimum voltage valueof the AC voltage is 1000 volts or more; the writing member writesinformation into the element in a non-contact state with respect to theelement; and the writing member writes, into the element, informationindicating a remaining amount or a usage amount of developer containedin the developing unit provided with the element.

The invention may also be an image forming apparatus comprising: aphotoconductor unit attach/detach section to and from which aphotoconductor unit having an element into which information can bewritten and a photoconductor can be attached and detached; a developingdevice for developing a latent image formed on the photoconductor; awriting member for writing information into the element; and an ACvoltage supply section for supplying an AC voltage, wherein, during aperiod from a start to an end of an image forming process, the writingmember writes information into the element of the photoconductor unitattached to the photoconductor unit attach/detach section when the ACvoltage supply section is not supplying an AC voltage.

If a photoconductor unit, which has an element into which informationcan be written and a photoconductor, is configured so that it can beattached to and detached from an photoconductor attach/detach section,then there is a possibility that the photoconductor unit attached to theattach/detach section will become detached. Consequently, it ispreferable that information about the photoconductor unit is suitablywritten into the element of that photoconductor unit. On the other hand,if an AC voltage supply section for supplying an AC voltage is provided,then when the AC voltage supply section is supplying an AC voltage,there is a possibility that electromagnetic noise will be generated inthe periphery of the AC voltage supply section.

With the foregoing image forming apparatus, the writing member writesinformation into the element of the photoconductor unit attached to thephotoconductor unit attach/detach section when the AC voltage supplysection is not supplying an AC voltage during the period from the startto the end of an image forming process, and thus information can bewritten accurately without being affected by noise caused by supplyingthe AC voltage, for example.

Further, in this image forming apparatus, the developing device may havea developer bearing body for bearing developer; and the AC voltagesupply section may supply an AC voltage to the developer bearing body.

With this image forming apparatus, the writing member writes informationinto the element of the photoconductor unit attached to thephotoconductor attach/detach section when the AC voltage supply sectionis not supplying an AC voltage to the developer bearing body during theperiod from the start to the end of an image forming process, and thusinformation can be written accurately without being affected by noisecaused by supplying the AC voltage to the developer bearing body, forexample.

Further, in this image forming apparatus, the photoconductor unit mayhave a charging member for charging the photoconductor; and the ACvoltage supply section may supply an AC voltage to the charging member.

With this image forming apparatus, the writing member writes informationinto the element of the photoconductor unit attached to thephotoconductor attach/detach section when the AC voltage supply sectionis not supplying an AC voltage to the charging member during the periodfrom the start to the end of an image forming process, and thusinformation can be written accurately without being affected by noisecaused by supplying the AC voltage to the charging member, for example.

Further, in this image forming apparatus, the developing device may be adeveloping unit that is provided as a unit; the image forming apparatusmay comprise a moving body provided with a plurality of developing unitattach/detach sections to and from which the developing unit can beattached and detached, and an attach/detach opening through which thedeveloping unit is attached to and detached from the developing unitattach/detach section; in a state in which the developing unit ispositioned at an opposing position where the developing unit is inopposition to the photoconductor due to movement of the moving body, thelatent image on the photoconductor may be developed with the developercontained in the developing unit; in a state in which the developingunit is positioned at a detaching position that is different from theopposing position due to movement of the moving body, the developingunit may be detached from the developing unit attach/detach section viathe attach/detach opening; and during a period from when the developingunit arrives at the opposing position until when the developing unitarrives at the detaching position due to movement of the moving body,the writing member may write information into the element of thephotoconductor unit.

If the developing unit, which has a developer containing section, isconfigured so that it can be attached to and detached from thedeveloping unit attach/detach section, then there is a possibility thatthe developing unit attached to the developing unit attach/detachsection may carelessly be detached via the attach/detach opening. Inthis case, if the photoconductor unit has an element and informationabout the developing unit is written into this element, then there is apossibility that information stored in the element may be incorrect ifthe developing unit is carelessly detached via the attach/detachopening.

Here, with the foregoing image forming device, the writing member writesinformation into the element of the photoconductor unit, without beingaffected by noise etc., during a period from when the developing unitarrives at the opposing position until when the developing unit arrivesat the detaching position due to movement of the moving body, and thus,even if the developer unit is carelessly detached via the attach/detachopening, it is possible to prevent the accuracy of the informationstored in the element from being impaired.

Further, in this image forming apparatus, during a period from when thedeveloper bearing body provided in the developing unit that has arrivedat the opposing position ends developing the latent image until when thedeveloping unit arrives at the detaching position, the writing membermay write information into the element of the photoconductor unit.

The amount of developer in the developing unit decreases when the latentimage is developed by the developer bearing body provided in thedeveloping unit. Here, with the foregoing image forming apparatus, thewriting member writes information into the element of the photoconductorunit during a period from when the developer bearing body provided inthe developing unit that has arrived at the opposing position endsdeveloping the latent image until when the developing unit arrives atthe detaching position. Consequently, for example, it becomes possibleto write information, such as the remaining amount based on the amountof developer that has decreased through development, into the element ofthe photoconductor unit.

Further, in this image forming apparatus, during a period from when thedeveloping unit starts moving from the opposing position until when thedeveloping unit arrives at the detaching position due to movement of themoving body, the writing member may write information into the elementof the photoconductor unit.

With this image forming apparatus, information can be writteneffectively using the period of time from when the developing unitstarts moving from the opposing position until when the developing unitarrives at the detaching position due to movement of the moving body.

Further, in this image forming apparatus, if, during the period fromwhen the developing unit starts moving from the opposing position untilwhen the developing unit arrives at the detaching position, anotherdeveloping unit adjacent to the developing unit on the upstream sidetherefrom in a direction of movement of the moving body arrives at theopposing position, then the writing member may write information intothe element of the photoconductor unit during a period until the otherdeveloping unit arrives at the opposing position.

With this image forming apparatus, the writing member writes informationinto the element of the developing unit during a period until the otherdeveloping unit arrives at the opposing position, and thus, informationwould already be written into the element, even if the developing unitis forcibly detached after the other developing unit has arrived at theopposing position, for example.

Further, in this image forming apparatus, a difference between a maximumvoltage value and a minimum voltage value of the AC voltage may be 1000volts or more.

When the difference between the maximum voltage value and the minimumvoltage value of the AC voltage is 1000 volts or more, theelectromagnetic noise that is generated also becomes large. With theforegoing image forming apparatus, the writing member writes informationinto the element of the photoconductor unit attached to thephotoconductor attach/detach section when the AC voltage supply sectionis not supplying an AC voltage during the period from the start to theend of an image forming process, and thus information can be writtenaccurately without being affected by the large noise caused by supplyingthe AC voltage, for example.

Further, in this image forming apparatus, the writing member may writeinformation into the element in a non-contact state with respect to theelement.

If the writing member writes information into the element in anon-contact state, then there is greater susceptibility toelectromagnetic noise than in the case where the writing member writesinformation into the element in a state in which it contacts theelement. With the foregoing image forming apparatus, the writing memberwrites information into the element of the photoconductor unit attachedto the photoconductor attach/detach section when the AC voltage supplysection is not supplying an AC voltage during the period from the startto the end of an image forming process, and thus information can bewritten accurately in a non-contact state without being affected by thelarge noise that is caused by supplying the AC voltage, for example.

It is also possible to achieve a computer system comprising: a computerunit; and an image forming apparatus connected to the computer unit, theimage forming apparatus including: an attach/detach section to and fromwhich a developing unit having an element into which information can bewritten and a developer bearing body can be attached and detached; aphotoconductor on which a latent image can be formed; a writing memberfor writing information into the element; and an AC voltage supplysection for supplying an AC voltage, wherein, during a period from astart to an end of an image forming process, the writing member writesinformation into the element of the developing unit attached to theattach/detach section when the AC voltage supply section is notsupplying an AC voltage.

It is also possible to achieve a computer system comprising: a computerunit; and an image forming apparatus connected to the computer unit, theimage forming apparatus including: a photoconductor unit attach/detachsection to and from which a photoconductor unit having an element intowhich information can be written and a photoconductor can be attachedand detached; a developing device for developing a latent image formedon the photoconductor; a writing member for writing information into theelement; and an AC voltage supply section for supplying an AC voltage,wherein, during a period from a start to an end of an image formingprocess, the writing member writes information into the element of thephotoconductor unit attached to the photoconductor unit attach/detachsection when the AC voltage supply section is not supplying an ACvoltage.

A developing unit comprises: a developer bearing body including arotating shaft and a large diameter section that has a diameter largerthan a diameter of the rotating shaft and that is for bearing developer,wherein the developer bearing body is capable of rotating about therotating shaft; an element with which communication is possible; and adeveloper containing section for containing developer, wherein theelement is provided more to the outside than the large diameter sectionin an axial direction of the rotating shaft.

With the foregoing developing unit, the element is provided more to theoutside than the large diameter section in an axial direction of therotating shaft, and thus, even if electromagnetic noise is generateddue, for example, to an AC voltage being applied to the developerbearing body, the negative influence of the noise on communication canbe reduced, and it becomes possible to achieve accurate communicationwith the element.

Further, the rotating shaft and the large diameter section may haveconductivity, and an AC voltage may be applied to them.

In such a case, since the degree to which the electromagnetic noiseaffects communication is conspicuous, the above-described effects, thatis, the effect that it becomes possible to reduce the negative influencethat the electromagnetic noise has on communication and the effect thatit becomes possible to achieve accurate communication with the elementare more effectively achieved.

Further, the developing unit may comprise a housing for forming thedeveloper containing section; and the element may be provided on thehousing.

In such a case, it is possible to achieve a developing unit in which theelement is provided at an easily attachable position.

Further, the developing unit may be capable of being attached to anddetached from one of a plurality of attach/detach sections which areprovided in a rotating body of an image forming apparatus body and toand from which the developing unit can be attached and detached; and theelement may be positioned more to the outside than a developing unitbody, which includes the developer bearing body and the developercontaining section, in a radial direction of rotation of the rotatingbody when the developing unit is attached to the attach/detach section.

In such a case, since the element is arranged more to the outside than adeveloping unit body in a radial direction of rotation of the rotatingbody, it becomes even easier to attach the element.

Further, the developing unit may be capable of being attached to anddetached from one of a plurality of attach/detach sections which areprovided in a rotating body of an image forming apparatus body and toand from which the developing unit can be attached and detached, theimage forming apparatus body further including an antenna for wirelesslycommunicating with the element of the developing unit attached to one ofthe attach/detach sections; and the element may be positioned more tothe inside than the antenna in a radial direction of rotation of therotating body when the developing unit is attached to the attach/detachsection.

In such a case, since the element is arranged more to the inside thanthe antenna in a radial direction of rotation of the rotating body, italso becomes easy to attach the antenna of the body for development.

Next, an image forming apparatus comprises: a developing unit includinga developer bearing body including a rotating shaft and a large diametersection that has a diameter larger than a diameter of the rotating shaftand that is for bearing developer, wherein the developer bearing body iscapable of rotating about the rotating shaft, an element with whichcommunication is possible, and a developer containing section forcontaining developer; an attach/detach section to and from which thedeveloping unit can be attached and detached; and an antenna forwirelessly communicating with the element of the developing unitattached to the attach/detach section, wherein the element is providedmore to the outside than the large diameter section in an axialdirection of the rotating shaft.

With the foregoing image forming apparatus, the element is provided moreto the outside than the large diameter section in an axial direction ofthe rotating shaft, and thus, even if electromagnetic noise is generateddue, for example, to an AC voltage being applied to the developerbearing body, the negative influence of the noise on communication canbe reduced, and it becomes possible to achieve accurate communicationwith the element.

Further, the rotating shaft and the large diameter section may haveconductivity, and an AC voltage may be applied to them.

In such a case, since the degree to which the electromagnetic noiseaffects communication is conspicuous, the above-described effects, thatis, the effect that it becomes possible to reduce the negative influencethat the electromagnetic noise has on communication and the effect thatit becomes possible to achieve accurate communication with the elementare more effectively achieved.

Further, the developing unit may have a housing for forming thedeveloper containing section, and the element may be provided on thehousing.

In such a case, it is possible to achieve an image forming apparatus inwhich the element is provided at an easily attachable position.

Further, the element may be positioned more to the outside than adeveloping unit body, which includes the developer bearing body and thedeveloper containing section, in a radial direction of rotation of therotating body when the developing unit is attached to the attach/detachsection.

In such a case, since the element is arranged more to the outside than adeveloping unit body in a radial direction of rotation of the rotatingbody, it becomes even easier to attach the element.

Further, the element may be positioned more to the inside than theantenna in a radial direction of rotation of the rotating body when thedeveloping unit is attached to the attach/detach section.

In such a case, since the element is arranged more to the inside thanthe antenna in a radial direction of rotation of the rotating body, italso becomes easy to attach the antenna of the body for development.

Further, the image forming apparatus may comprise an attach/detachopening through which the developing unit is attached to and detachedfrom the attach/detach section, and a photoconductor on which a latentimage can be formed; in a state in which the developing unit ispositioned at an opposing position where the developing unit is inopposition to the photoconductor due to rotation of the rotating body,the latent image may be developed with the developer contained in thedeveloping unit; in a state in which the developing unit is positionedat a detaching position that is different from the opposing position dueto rotation of the rotating body, the developing unit may be detachedfrom the attach/detach section via the attach/detach opening; and duringa period from when the developing unit arrives at the opposing positionuntil when the developing unit arrives at the detaching position due torotation of the rotating body, the image forming apparatus may writeinformation into the element of the developing unit using the antenna.

If the image forming apparatus is provided with an attach/detach openingthrough which the developing unit is attached to and detached from theattach/detach section, then there is a possibility that a developingunit attached to the attach/detach section may carelessly be detachedvia the attach/detach opening. In particular, since the amount ofdeveloper in a developing unit decreases when the developing unit ispositioned at the opposing position and development is carried out, ifthe developing unit is detached before information about the amount ofdeveloper that has decreased is written into its element, then it maynot be possible to ascertain the amount of developer contained in thedeveloping unit, for example.

It becomes possible to solve the this problem in cases such as thosedescribed above.

Further, the image forming apparatus may comprise an AC voltage supplysection for supplying an AC voltage; and the image forming apparatus maywrite information into the element of the developing unit attached tothe attach/detach section using the antenna when the AC voltage supplysection is supplying an AC voltage to the developer bearing body.

In such a case, since there is an increased possibility that theelectromagnetic noise will negatively affect communication becauseinformation is written into the element when the AC voltage supplysection is supplying an AC voltage to the developer bearing body, theabove-described effects, that is, the effect that it becomes possible toreduce the negative influence that the electromagnetic noise has oncommunication and the effect that it becomes possible to achieveaccurate communication with the element are more effectively achieved.

Further, a difference between a maximum voltage value and a minimumvoltage value of the AC voltage may be 1000 volts or more.

When the difference between the maximum voltage value and the minimumvoltage value of the AC voltage is 1000 volts or more, theelectromagnetic noise that is generated also becomes large, andtherefore, the above-described effects, that is, the effect that itbecomes possible to reduce the negative influence that theelectromagnetic noise has on communication and the effect that itbecomes possible to achieve accurate communication with the element aremore effectively achieved.

Further, the antenna may be capable of communicating with the element ina non-contact state with respect to the element.

In such a case, since the environment pertaining to the communicationbetween the antenna and the element is severe compared to a case where,for example, communication is carried out in a state in which they arein contact with each other, the above-described effects, that is, theeffect that it becomes possible to reduce the negative influence thatthe electromagnetic noise has on communication and the effect that itbecomes possible to achieve accurate communication with the element aremore effectively achieved.

It is also possible to achieve an image forming apparatus comprising: adeveloping unit including a developer bearing body including a rotatingshaft and a large diameter section that has a diameter larger than adiameter of the rotating shaft and that is for bearing developer,wherein the developer bearing body is capable of rotating about therotating shaft, an element with which communication is possible, and adeveloper containing section for containing developer; an attach/detachsection to and from which the developing unit can be attached anddetached; and an antenna for wirelessly communicating with the elementof the developing unit attached to the attach/detach section, wherein:the element is provided more to the outside than the large diametersection in an axial direction of the rotating shaft; the rotating shaftand the large diameter section have conductivity, and an AC voltage isapplied to them; the developing unit has a housing for forming thedeveloper containing section, and the element is provided on thehousing; the element is positioned more to the outside than a developingunit body, which includes the developer bearing body and the developercontaining section, in a radial direction of rotation of the rotatingbody when the developing unit is attached to the attach/detach section;the element is positioned more to the inside than the antenna in aradial direction of rotation of the rotating body when the developingunit is attached to the attach/detach section; the image formingapparatus comprises an attach/detach opening through which thedeveloping unit is attached to and detached from the attach/detachsection, and a photoconductor on which a latent image can be formed; ina state in which the developing unit is positioned at an opposingposition where the developing unit is in opposition to thephotoconductor due to rotation of the rotating body, the latent imagecan be developed with the developer contained in the developing unit; ina state in which the developing unit is positioned at a detachingposition that is different from the opposing position due to rotation ofthe rotating body, the developing unit can be detached from theattach/detach section via the attach/detach opening; during a periodfrom when the developing unit arrives at the opposing position untilwhen the developing unit arrives at the detaching position due torotation of the rotating body, the image forming apparatus writesinformation into the element of the developing unit using the antenna;the image forming apparatus comprises an AC voltage supply section forsupplying an AC voltage; the image forming apparatus writes informationinto the element of the developing unit attached to the attach/detachsection using the antenna when the AC voltage supply section issupplying an AC voltage to the developer bearing body; a differencebetween a maximum voltage value and a minimum voltage value of the ACvoltage is 1000 volts or more; and the antenna is capable ofcommunicating with the element in a non-contact state with respect tothe element.

It is also possible to achieve a computer system comprising: a computerunit; a display device that is capable of being connected to thecomputer unit; and an image forming apparatus that is capable of beingconnected to the computer unit, the image forming apparatus including: adeveloping unit including a developer bearing body including a rotatingshaft and a large diameter section that has a diameter larger than adiameter of the rotating shaft and that is for bearing developer,wherein the developer bearing body is capable of rotating about therotating shaft, an element with which communication is possible, and adeveloper containing section for containing developer; an attach/detachsection to and from which the developing unit can be attached anddetached; and an antenna for wirelessly communicating with the elementof the developing unit attached to the attach/detach section, whereinthe element is provided more to the outside than the large diametersection in an axial direction of the rotating shaft.

FIRST EMBODIMENT

Overview of Image Forming Apparatus (Laser Beam Printer)

Next, using FIG. 1 and FIG. 2, an overview of a laser beam printer(hereinafter, also referred to as “printer”) 10, taken as an example ofthe image forming apparatus, is described. FIG. 1 is a diagram fordescribing a configuration in which a developing unit 54 (51, 52, 53)and a photoconductor unit 75 are attached to and detached from a printerunit 10 a. FIG. 2 is a diagram showing main structural components thatconfigure the printer 10. It should be noted that FIG. 2 is a diagram ofa cross section taken perpendicular to the X direction in FIG. 1.Further, the up/down direction is shown by an arrow in FIG. 1 and FIG.2, and for example, a paper supply tray 92 is arranged at a lowersection of the printer 10 and a fusing unit 90 is arranged at an uppersection of the printer 10.

<Attach/Detach Configuration>

The developing unit 54 (51, 52, 53) and the photoconductor unit 75 canbe attached to and detached from the printer unit 10 a. The printer 10is structured by attaching the developing unit 54 (51, 52, 53) and thephotoconductor unit 75 to the printer unit 10 a.

The printer unit 10 a has a first open/close cover 10 b that can beopened and closed, a second open/close cover 10 c that can be opened andclosed and that is provided more inward than the first open/close cover10 b, a photoconductor unit attach/detach opening 10 d through which thephotoconductor unit 75 is attached and detached, and a developing unitattach/detach opening 10 e through which the developing unit 54 (51, 52,53) is attached and detached.

Here, when the user opens the first open/close cover 10 b, thephotoconductor unit 75 can be attached to and detached from the printerunit 10 a via the photoconductor unit attach/detach opening 10 d.Further, when the user opens the second open/close cover 10 c, thedeveloping unit 54 (51, 52, 53) can be attached to and detached from theprinter unit 10 a via the developing unit attach/detach opening 10 e.

<Overview of the Printer 10>

An overview of the printer 10 in a state in which the developing unit 54(51, 52, 53) and the photoconductor unit 75 have been attached to theprinter unit 10 a is described.

As shown in FIG. 2, the printer 10 according to the present embodimenthas a charging unit 30, an exposing unit 40, a YMCK developing device50, a first transferring unit 60, an intermediate transferring body 70,and a cleaning blade 76, in the direction of rotation of aphotoconductor 20, which is a latent image bearing body for bearing alatent image. It further includes a second transferring unit 80, afusing unit 90, a display unit 95 made of a liquid crystal panel etc.for constituting a means for making a notification to the user, and acontrol unit 100 (FIG. 3) for controlling these units etc. so as tocontrol the operation of the printer 10.

The photoconductor 20 has a cylindrical conductive base and aphotoconductive layer formed on the outer circumference surface of thisbase, and can rotate about a central shaft. In this embodiment, thephotoconductor rotates in the clockwise direction as shown by arrow inFIG. 2.

The charging unit 30 is a device for charging the photoconductor 20, andthe exposing unit 40 is a device for forming a latent image on thecharged photoconductor 20 by irradiating laser. The exposing unit 40has, for example, a semiconductor laser, a polygon mirror, and an F-θlens, and irradiates modulated laser onto the charged photoconductor 20based on an image signal that is input from a not-shown host computer,such as a personal computer or a word processor.

The YMCK developing device 50 has a rotary 55, which serves as a movingbody, and four developing units attached to the rotary 55. The rotary 55is capable of rotating, and is provided with four attach/detach sections55 b, 55 c, 55 d, and 55 e to and from which the four developing units51, 52, 53, and 54 can respectively be attached and detached via thedeveloping unit attach/detach opening 10 e. The cyan developing unit 51,which contains cyan (C) toner, can be attached to and detached from theattach/detach section 55 b, the magenta developing unit 52, whichcontains magenta (M) toner, can be attached to and detached from theattach/detach section 55 c, the black developing unit 53, which containsblack (K) toner, can be attached to and detached from the attach/detachsection 55 d, and the yellow developing unit 54, which contains yellow(Y) toner, can be attached to and detached from the attach/detachsection 55 e.

By rotating, the rotary 55 moves the above-mentioned four developingunits 51, 52, 53, and 54 that have been attached to the attach/detachsections 55 b, 55 c, 55 d, and 55 e, respectively. That is, the rotary55 rotates the four attached developing units 51, 52, 53, and 54 about acentral shaft 55 a while maintaining their relative positions. Then, thedeveloping units 51, 52, 53, and 54 are selectively brought intoopposition with the latent image formed on the photoconductor 20 so asto develop the latent image on the photoconductor 20 using the tonercontained in each of the developing units 51, 52, 53, and 54. It shouldbe noted that the developing units are described in detail later.

The first transferring unit 60 is a device for transferring asingle-color toner image formed on the photoconductor 20 onto theintermediate transferring body 70. When the four colors of toner aresuccessively transferred over one another, a full-color toner image isformed on the intermediate transferring body 70.

The intermediate transferring body 70 is an endless belt and isrotatably driven at substantially the same circumferential velocity asthe photoconductor 20. A read sensor for synchronization RS is providednear the intermediate transferring body 70. The read sensor forsynchronization RS is a sensor for detecting the reference position ofthe intermediate transferring body 70, and obtains a synchronizationsignal Vsync in the sub-scanning direction, which is perpendicular tothe main scanning direction. The read sensor for synchronization RS hasa light-emitting section for emitting light and a light-receivingsection for receiving light. Light that is emitted from thelight-emitting section passes through a hole formed in a predeterminedposition of the intermediate transferring body 70, and when light isreceived by the light-receiving section, the read sensor forsynchronization RS generates a pulse signal. One pulse signal isgenerated each time the intermediate transferring body 70 makes onerevolution.

The second transferring unit 80 is a device for transferring thesingle-color toner image or the full-color toner image formed on theintermediate transferring body 70 onto a recording medium such as paper,film, or cloth.

The fusing unit 90 is a device for fusing the single-color toner imageor the full-color toner image, which has been transferred onto therecording medium, onto the recording medium, such as paper, to make theimage into a permanent image.

The cleaning blade 76 is made of rubber and abuts against the surface ofthe photoconductor 20. The cleaning blade 76 removes the toner remainingon the photoconductor 20 by scraping it off after the toner image hasbeen transferred onto the intermediate transferring body 70 by the firsttransferring unit 60.

The photoconductor unit 75 is provided between the first transferringunit 60 and the exposing unit 40, and has the photoconductor 20, anelement 75 a to which information can be written, the charging unit 30,the cleaning blade 76, and a waste toner containing section 76 a forcontaining toner that has been scraped off by the cleaning blade 76. Itshould be noted that the element 75 a has a configuration that allowsstorage of various types of information that have been written in.

The control unit 100 is made of a main controller 101 and a unitcontroller 102, as shown in FIG. 3. An image signal is input to the maincontroller 101, and in accordance with a command based on this imagesignal, the unit controller 102 controls each of the above-mentionedunits etc. to form an image.

Operation of Printer 10

Next, the operation of the printer 10 configured as above is describedwith reference to other structural components thereof.

First, when an image signal from a not-shown host computer is input tothe main controller 101 of the printer 10 via an interface (I/F) 112,the photoconductor 20 and the intermediate transferring body 70 arerotated due to control by the unit controller 102 based on a commandfrom the main controller 101. Then, the reference position of theintermediate transferring body 70 is detected by the read sensor forsynchronization RS, and a pulse signal is output. This pulse signal issent to the unit controller 102 via a serial interface 121. The unitcontroller 102 controls the following operation, taking the pulsesignal, which has been received, as a reference.

While rotating, the photoconductor 20 is successively charged by thecharging unit 30 at a charging position. The area of the photoconductor20 that has been charged is brought to an exposing position through therotation of the photoconductor 20, and a latent image corresponding toimage information for a first color, for example, yellow Y, is formed inthat area by the exposing unit 40.

The latent image formed on the photoconductor 20 is brought to adeveloping position through the rotation of the photoconductor 20, andis developed with yellow toner by the yellow developing unit 54. Ayellow toner image is thus formed on the photoconductor 20.

The yellow toner image that has been formed on the photoconductor 20 isbrought to a first transferring position through the rotation of thephotoconductor 20 and is transferred onto the intermediate transferringbody 70 by the first transferring unit 60. At this time, a firsttransferring voltage that has a polarity that is opposite from thetoner-charge polarity is applied to the first transferring unit 60. Itshould be noted that throughout this operation, the second transferringunit 80 is separated from the intermediate transferring body 70.

The above process is repeated for the second color, the third color, andthe fourth color, and therefore, toner images of each colorcorresponding to each of the image signals are transferred onto theintermediate transferring body 70 in a superposed manner. Thus, afull-color toner image is formed on the intermediate transferring body70.

The full-color toner image that has been formed on the intermediatetransferring body 70 is brought to a second transferring positionthrough the rotation of the intermediate transferring body 70 and istransferred onto a recording medium by the second transferring unit 80.It should be noted that the recording medium is carried from the papersupply tray 92 to the second transferring unit 80 via a paper supplyroller 94 and a resist roller 96. Further, when performing thetransferring operation, the second transferring unit 80 is pressedagainst the intermediate transferring body 70 and supplied with a secondtransferring voltage.

The fusing unit 90 heats and applies pressure to the full-color tonerimage that has been transferred to the recording medium, and the imageis fused to the recording medium.

On the other hand, after the photoconductor 20 passes the firsttransferring position, the toner adhering to its surface is scraped offby the cleaning blade 76 and it is prepared for charging for forming thenext latent image. The toner that has been scraped off is collected inthe waste toner containing section 76 a.

Overview of Control Unit

Next, the configuration of the control unit 100 is described withreference to FIG. 3. FIG. 3 is a block diagram showing the control unit100 provided in the printer 10.

The main controller 101 of the control unit 100 is connected to a hostcomputer via the interface 112, and is provided with an image memory 113for storing image signals that are received from the host computer.

The unit controller 102 of the control unit 100 is electricallyconnected to each of the units (the charging unit 30, the exposing unit40, the first transferring unit 60, the photoconductor unit 75, thesecond transferring unit 80, the fusing unit 90, and the display unit95) and the YMCK developing device 50, and by receiving signals from thesensors provided in these components, the unit controller controls eachof these units and the YMCK developing device 50 based on signals inputfrom the main controller 101 as it detects the state of each of theseunits and the YMCK developing device 50. As the structural componentsfor driving each of these units and the YMCK developing device 50, FIG.3 shows a photoconductor unit drive control circuit, a charging unitdrive control circuit, an exposing unit drive control circuit 127, aYMCK developing device drive control circuit 125, a first transferringunit drive control circuit, a second transferring unit drive controlcircuit, a fusing unit drive control circuit, and a display unit drivecontrol circuit.

The exposing unit drive control circuit 127 connected to the exposingunit 40 has a pixel counter 127 a that serves as consumption amountdetection means for detecting the amount of consumption of developer.The pixel counter 127 a counts the number of pixels that are input tothe exposing unit 40. It should be noted that it is also possible toprovide the pixel counter 127 a in the exposing unit 40 or in the maincontroller 101. It should be noted that the number of pixels is thenumber of pixels in units of basic resolution of the printer 10, or inother words, the number of pixels of the image that is actually printed.The amount of consumption of toner T (the usage amount) is proportionalto the number of pixels, and therefore, by counting the number ofpixels, it is possible to detect the amount of consumption of toner T.

To the YMCK developing device drive control circuit 125, an AC voltageis supplied from an AC voltage supply section 126 a and a DC voltage issupplied from a DC voltage supply section 126 b. The YMCK developingdevice drive control circuit 125 applies a voltage, which is obtained bysuperimposing the AC voltage and the DC voltage, to a developing rollerat a suitable timing to form an alternating electric field between thedeveloping roller and the photoconductor.

Further, the CPU 120 provided in the unit controller 102 is connected toa nonvolatile storage element (hereinafter, also referred to as“printer-side memory”) 122 such as a serial EEPROM via the serialinterface (I/F) 121.

Further, the CPU 120 is capable of wirelessly communicating withelements 51 a, 52 a, 53 a, and 54 a respectively provided in/on thedeveloping units 51, 52, 53, and 54 via the serial interface 121, asend/receive circuit 123, and a printer-side antenna (antenna forcommunicating with the developing unit elements) 124 b that serves as anantenna for wirelessly communicating with the elements of the developingunits. The CPU 120 is also capable of wirelessly communicating with theelement 75 a of the photoconductor unit 75 via the serial interface 121,the send/receive circuit 123, and a printer-side antenna (antenna forcommunicating with the photoconductor unit element) 124 a. At the timeof wireless communication, the antenna 124 b for communicating with thedeveloping unit elements, which serves as a writing member (writingmeans), writes information into the elements 51 a, 52 a, 53 a, and 54 aof the developing units 51, 52, 53, and 54, respectively. The antenna124 b for communicating with the developing unit elements is alsocapable of reading information from the elements 51 a, 52 a, 53 a, and54 a of the developing units 51, 52, 53, and 54, respectively. At thetime of wireless communication, the antenna 124 a for communicating withthe photoconductor unit element, which serves as a writing member(writing means), writes information into the element 75 a of thephotoconductor unit 75. The antenna 124 a for communicating with thephotoconductor unit element can also read information from the element75 a of the photoconductor unit 75.

Overview of Developing Units

Next, an overview of the developing units is described using FIG. 4 andFIG. 5. FIG. 4 is a perspective view of the yellow developing unit 54seen from the side of a developing roller 510. FIG. 5 is across-sectional view showing main structural components of the yellowdeveloping unit 54. It should be noted that in FIG. 5 as well, theup/down direction is shown by an arrow, and for example, the centralaxis of the developing roller 510 is located lower than the central axisof the photoconductor 20. Further, in FIG. 5, the yellow developing unit54 is shown in a state in which it is positioned at a developingposition that is in opposition to the photoconductor 20.

The YMCK developing device 50 is provided with the cyan developing unit51, which contains cyan (C) toner, the magenta developing unit 52, whichcontains magenta (M) toner, the black developing unit 53, which containsblack (K) toner, and the yellow developing unit 54, which containsyellow (Y) toner. Since the configuration of each of these developingunits is the same, the yellow developing unit 54 is described below.

The yellow developing unit 54 is provided with, for example, a developercontaining section, that is, a first containing section 530 and a secondcontaining section 535 for containing yellow toner T which serves as thedeveloper, the element 54 a, a housing 540 for forming the developercontaining section, the developing roller 510 which serves as thedeveloper bearing body, a toner supply roller 550 for supplying toner Tto the developing roller 510, and a restriction blade 560 forrestricting the thickness of the layer of toner T that is bore on thedeveloping roller 510.

The housing 540 is manufactured by joining, for example, an upperhousing and a lower housing which have been integrally molded, and theinside of the housing is divided into the first containing section 530and the second containing section 535 by a restriction wall 545 thatextends upward from the lower section (in the up/down direction of FIG.5). The first containing section 530 and the second containing section535 form developer containing sections (530, 535) for containing toner Twhich serves as a developer. The upper sections of the first containingsection 530 and the second containing section 535 are in communication,and the movement of the toner T between them is restricted by therestriction wall 545. It should be noted that it is also possible toprovide a stirring member for stirring the toner T contained in thefirst containing section 530 and the second containing section 535. Inthe present embodiment, however, each of the developing units (the cyandeveloping unit 51, the magenta developing unit 52, the black developingunit 53, and the yellow developing unit 54) rotates in conjunction withthe rotation of the rotary 55 so that the toner Tin each developing unitis stirred. Therefore, a stirring member is not provided in the firstcontaining section 530 or the second containing section 535.

The element 54 a, into which information can be written, is provided onthe outer surface of the housing 540. The element 54 a has aconfiguration that allows storage of information that has been writtenin, and details thereof will be described later.

An opening 541 that communicates with the outside of the housing 540 isprovided in the lower section of the first containing section 530. Thetoner supply roller 550 is provided in the first containing section 530with its circumferential surface facing the opening 541, and isrotatably supported on the housing 540. Further, the developing roller510 is provided with its circumferential surface facing the opening 541from outside the housing 540, and the developing roller 510 abutsagainst the toner supply roller 550.

The developing roller 510 bears toner T and carries the toner to adeveloping position, which is in opposition to the photoconductor 20.The developing roller 510 is made of, for example, aluminum, stainlesssteel, or iron, and if necessary, it can be subjected to nickel platingor chromium plating, and the toner bearing region can be subjected tosandblasting or the like. Further, the developing roller 510 can rotateabout its central axis, and as shown in FIG. 5, it rotates in theopposite direction (in FIG. 5, the counterclockwise direction) to therotating direction of the photoconductor 20 (in FIG. 5, the clockwisedirection). Its central axis is located lower than the central axis ofthe photoconductor 20. Further, as shown in FIG. 5, in a state in whichthe yellow developing unit 54 is in opposition to the photoconductor 20,a gap exists between the developing roller 510 and the photoconductor20. That is, the yellow developing unit 54 develops the latent imageformed on the photoconductor 20 in a non-contacting state. It should benoted that when the latent image formed on the photoconductor 20 isdeveloped, an alternating electric field is generated between thedeveloping roller 510 and the photoconductor 20.

The toner supply roller 550 supplies, to the developing roller 510, thetoner T contained in the first containing section 530 and the secondcontaining section 535. The toner supply roller 550 is made ofpolyurethane foam, for example, and abuts against the developing roller510 in a state in which it is elastically deformed. The toner supplyroller 550 is arranged at a lower section of the first containingsection 530, and the toner T contained in the first containing section530 and the second containing section is supplied to the developingroller 510 by the toner supply roller 550 at the lower section of thefirst containing section 530. The toner supply roller 550 can rotateabout its central axis, and its central axis is located lower than thecentral rotation axis of the developing roller 510. Further, the tonersupply roller 550 rotates in the opposite direction (in FIG. 5, theclockwise direction) to the rotating direction of the developing roller510 (in FIG. 5, the counterclockwise direction). It should be noted thatthe toner supply roller 550 has the function of supplying the toner Tthat is contained in the first containing section 530 and the secondcontaining section 535 to the developing roller 510 as well as thefunction of stripping off, from the developing roller 510, the toner Tthat remains on the developing roller 510 after development.

The restriction blade 560 restricts the thickness of the toner T layerbore by the developing roller 510, and gives charge to the toner T boreby the developing roller 510. The restriction blade 560 has a rubbersection 560 a and a rubber support section 560 b. The rubber section 560a is made of, for example, silicone rubber or urethane rubber, and therubber support section 560 b is a thin plate made of, for example,phosphor bronze or stainless steel, and has a springy characteristic.The rubber section 560 a is supported by the rubber support section 560b, and one end of the rubber support section 560 b is fixed to a bladesupport metal plate 562. The blade support metal plate 562 is fastenedto a seal frame 526, which is described later, and is attached to thehousing 540 together with the restriction blade 560, forming a part of aseal unit 520, which is described later. In this state, the rubbersection 560 a is pressed against the developing roller 510 by theelastic force created by the flexure of the rubber support section 560b.

Further, a blade backing member 570 made of Moltoprene or the like isprovided on one side of the restriction blade 560 opposite from the sideof developing roller 510. The blade backing member 570 prevents thetoner T from entering in between the rubber support section 560 b andthe housing 540 to stabilize the elastic force caused by the flexure ofthe rubber support section 560 b, and also presses the rubber section560 a against the developing roller 510 by applying force to the rubbersection 560 a toward the developing roller 510 from directly behind therubber section 560 a. Consequently, the blade backing member 570improves the contact uniformity and the sealing properties of the rubbersection 560 a with respect to the developing roller 510.

The end of the restriction blade 560 on the side opposite from the sidesupported by the blade support metal plate 562, that is, its tip, is notin contact with the developing roller 510; rather, a section at apredetermined distance from its tip contacts, with some breadth, thedeveloping roller 510. That is, the restriction blade 560 does not abutagainst the developing roller 510 at its edge but rather at its midsection. Further, the restriction blade 560 is arranged such that itstip is facing upstream in the rotating direction of the developingroller 510, and thus, makes a so-called counter-abutment with respect tothe roller. It should be noted that the abutting position where therestriction blade 560 abuts against the developing roller 510 is locatedlower than the central axis of the developing roller 510 and is alsolocated lower than the central axis of the toner supply roller 550.

The seal member 520 prevents the toner T in the yellow developing unit54 from spilling out from the unit, and also collects the toner T on thedeveloping roller 510, which has passed the developing position, intothe developing unit without scraping it off. The seal member 520 is aseal made of polyethylene film or the like. The seal member 520 issupported by a seal support metal plate 522, and is attached to theframe 540 via the seal support metal plate 522. A seal urging member 524made of Moltoprene or the like is provided on one side of the sealmember 520 opposite from the side of the developing roller 510, and dueto the elastic force of the seal urging member 524, the seal member 520is pressed against the developing roller 510. It should be noted thatthe abutting position where the seal member 520 abuts against thedeveloping roller 510 is located above the central axis of thedeveloping roller 510.

In the yellow developing unit 54 configured in this manner, the tonersupply roller 550 supplies, to the developing roller 510, the toner Tthat is contained in the first containing section 530 and the secondcontaining section 535, which serve as developer containing sections.The toner T that is supplied to the developing roller 510 is brought tothe abutting position of the restriction blade 560 in conjunction withthe rotation of the developing roller 510, and when it passes theabutting position, the thickness of the toner layer is restricted andthe toner is charged. Then, due to further rotation of the developingroller 510, the toner T on the developing roller 510, whose layerthickness has been restricted, is brought to the developing positionopposing the photoconductor 20, and is used for developing the latentimage formed on the photoconductor 20 under the alternating electricfield at the developing position. The toner T on the developing roller510 that has passed the developing position due to further rotation ofthe developing roller 510 passes the seal member 520 and is collectedinto the developing unit by the seal member 520 without being scrapedoff.

Configuration of Elements

Next, the configuration of the elements of the developing units and theelement of the photoconductor unit, including the configuration forsending and receiving data, is described with reference to FIG. 6A, FIG.6B, FIG. 7, and FIG. 8. FIG. 6A is a plan perspective view showing theconfiguration of an element. FIG. 6B is a block diagram for describingthe internal configuration of the element and the send/receive section.FIG. 7 is a diagram for describing the information stored in a memorycell 54 h of the element 54 a. FIG. 8 is a diagram for describing theinformation stored in the memory cell of the element 54 a of thephotoconductor unit 75.

Since the elements of the developing units other than the yellowdeveloping unit 54 also have the same configuration, the element 54 a ofthe yellow developing unit 54 is taken as an example and describedbelow.

If the element 54 a and the printer-side antenna 124 b are in apredetermined positional relationship, for example, if they are within10 mm of one another, information can be sent and received without theelement and the antenna being in contact with one another. The element54 a is overall very compact and thin, and one of its sides can be madeadhesive and can be made to adhere to an object as a sticker. It isknown as a memory tag, for example, and is sold commercially in variousforms.

The element 54 a has a non-contact IC chip 54 b, a resonant capacitor 54c that is formed by etching a metal film, and a flat coil serving as anantenna 54 d. These are mounted onto a plastic film and covered by atransparent coversheet.

The printer unit 10 a has a coil that serves as the printer-side antenna124 b, the send/receive circuit 123, and the serial interface 121 thatis connected to the controller (CPU) 120 of the printer unit 10 a.

The non-contact IC chip 54 b has a rectifier 54 e, a signal analysissection RF (Radio Frequency) 54 f, a controller 54 g, and the memorycell 54 h. The memory cell 54 h is a nonvolatile memory that can beelectrically read and written, such as an NAND flash ROM, and is capableof storing information that has been written and allows the storedinformation to be read from the outside.

The antenna 54 d of the element 54 a and the printer-side antenna 124 bwirelessly communicate with one another to read information stored inthe memory cell 54 h and write information into the memory cell 54 h.Further, the high frequency signals that are generated by thesend/receive circuit 123 of the printer unit 10 a are induced as a highfrequency magnetic field via the printer-side antenna 124 b. This highfrequency magnetic field is absorbed via the antenna 54 d of the element54 a, is rectified by the rectifier 54 e, and becomes a DC power sourcefor driving each of the circuits in the IC chip 54 b.

The memory cell 54 h of the element 54 a stores various types ofinformation, as shown in FIG. 7. The address 00H stores unique IDinformation for each element, such as the serial-number of the element.The address 01H stores the date that the developing unit wasmanufactured. The address 02H stores information for specifying thedestination of the developing unit. The address 03H stores informationfor specifying the manufacturing line on which the developing unit wasmanufactured. The address 04H stores information for specifying modelswith which the developing unit is compatible. The address 05H storestoner remaining amount information as information indicating the amountof toner that is contained in the developing unit. The address 06H andsubsequent areas store appropriate information.

The ID information that is stored on the memory cell 54 h of the element54 a can be written at the time that the storage element is manufacturedin the factory. The main unit of the printer 10 can read this IDinformation to identify each of the elements 54 a, 51 a, 52 a, and 53 a.

It should be noted that the element 75 a of the photoconductor unit 75has the same configuration. The memory cell of the element of thephotoconductor unit 75 stores various types of information, as shown inFIG. 8.

The address 00H stores unique ID information for each element, such asthe serial number of the element. The address 01H stores the date thatthe photoconductor unit was manufactured. The address 02H storesinformation for specifying the destination of the photoconductor unit.The address 03H stores information for specifying the manufacturing lineon which the photoconductor unit was manufactured. The address 04Hstores information for specifying models with which the photoconductorunit is compatible. The address 05H stores information indicating thetotal number of printed sheets of the printer unit 10 a when thephotoconductor unit is attached to the printer unit 10 a. The address06H stores information indicating the total number of printed sheets ofthe printer unit 10 a when the photoconductor unit has reached itsservice life and is detached from the printer unit 10 a. The address 07Hstores the number of sheets for which color printing has been performedusing the photoconductor unit. The address 08H stores the number ofsheets for which monochrome printing has been performed using thephotoconductor unit. The area of address 09H also stores appropriateinformation.

Relationship Between Element and Printer-side Antenna

Next, the relationship between the elements of the developing units andthe printer-side antenna 124 b, also with consideration to therelationship with the developing unit attach/detach opening 10 e, isdescribed with reference to FIG. 9A, FIG. 9B, and FIG. 9C. FIG. 9A is adiagram for describing the relationship between the element and theprinter-side antenna when the yellow developing unit 54 is positioned atthe developing position. FIG. 9B is a diagram for describing therelationship between the element and the printer-side antenna when theyellow developing unit 54 is positioned at the attach/detach position.FIG. 9C is a diagram for describing the relationship between the elementand the printer-side antenna when the rotary 55 is positioned at thehome position.

In FIG. 9A, the yellow developing unit 54 is positioned at thedeveloping position (opposing position), and the element 54 a of theyellow developing unit 54 is in opposition to the printer-side antenna124 b in a non-contact state. The printer-side antenna 124 b, as shownin FIG. 9A, is provided so that the element 54 a is positioned more tothe inside than the printer-side antenna 124 b in the radial directionof rotation of the rotary 55. It should be noted that the element 54 ais positioned more to the outside than the body of the yellow developingunit in the radial direction of rotation of the rotary 55.

The printer-side antenna 124 b is provided so that its longitudinaldirection (in FIG. 9A to FIG. 9C, the Y direction) is in the directionof rotation of the rotary 55 (in FIG. 9A to FIG.9C, the Z direction). Byarranging the printer-side antenna 124 b in this manner, wirelesscommunication can be carried out effectively between the printer-sideantenna 124 b and the element 54 a. That is, the printer-side antenna124 b can wirelessly communicate with the element 54 a not only in thestate shown in FIG. 9A but also in a state in which the rotary 55 hasbeen rotated by a predetermined angle. By making the longitudinaldirection of the printer-side antenna 124 b follow the direction ofrotation of the rotary 55, the range of angle of rotation of the rotary55 in which wireless communication is possible can be made large.

It should be noted that the printer-side antenna 124 b can wirelesslycommunicate with the element 54 a not only when the rotary 55 is in astopped state but also when the rotary 55 is in a moving state. That is,the printer-side antenna 124 b can wirelessly communicate with theelement 54 a even if the element is moving.

FIG. 9B is a diagram showing a state in which the rotary 55 ispositioned at the attach/detach position where the yellow developingunit 54 can be attached and detached via the developing unitattach/detach opening 10 e. In the state shown in FIG. 9B, the yellowdeveloping unit 54 can be attached to and detached from theattach/detach section 55 e via the developing unit attach/detach opening10 e. Further, FIG. 9C shows a state in which the rotary 55 ispositioned at the home position after the printer 10 has been turned ONand the initialization operation has been performed.

The same applies for the relationship between the printer-side antenna124 a and the element 75 a of the photoconductor unit 75. Theprinter-side antenna 124 a is in opposition to the element 75 a of thephotoconductor unit 75 in a non-contact state (see FIG. 2), and theprinter-side antenna 124 a can wirelessly communicate with the element75 a of the photoconductor unit 75 in a non-contact state.

Rotation of Rotary 55 and Attach/Detach Position (Attaching andDetaching Position) of Developing Units

Next, the relationship between the rotation of the rotary 55 and theposition where the developing units are detached is described withreference again to FIG. 9A to FIG. 9C.

As described above, in the state shown in FIG. 9A, the yellow developingunit 54 is positioned at the developing position. When the rotary 55 isrotated from this state by a predetermined angle in the Z direction, thestate shown in FIG. 9B is attained. In the state shown in FIG. 9B, theyellow developing unit 54 is positioned at a position where it can beattached and detached. In this state, the yellow developing unit 54 canbe attached and detached via the attach/detach opening 10 e, that is, itcan be mounted to the attach/detach section 55 e or it can be removedfrom the attach/detach section 55 e. Then, when the rotary 55 is rotatedfrom the state shown in FIG. 9B by a predetermined angle in the Zdirection, the cyan developing unit 51, which is positioned upstream inthe direction of rotation of the rotary 55, is positioned at thedeveloping position.

It should be noted that FIG. 9C shows a state in which the rotary 55 ispositioned at the home position after the printer 10 has been turned ONand the initialization operation has been performed.

Writing Information into Elements of Developing Units

Next, the writing of information into the elements of the developingunits is described with reference to FIG. 10. FIG. 10 is a flowchart fordescribing how information is written into the elements of thedeveloping units.

<Step of Standby for Image Forming Process (Step 1)>

When the printer 10 is turned ON, a predetermined initializationoperation is performed, and the printer 10 enters an image formingprocess standby state. When an image signal, which is an image formingprocess command from the host computer, is input to the main controller101 of the printer 10 via the interface (I/F) 112, the photoconductor 20and the intermediate transferring body 70 are rotated. Then, the readsensor for synchronization RS detects the reference position of theintermediate transferring body 70 and outputs a pulse signal. The unitcontroller 102 executes the following control, taking the pulse signalthat has been received as a reference.

<Step of Starting Counting Number of Yellow Pixels (Step 3)>

A latent image that corresponds to the yellow image 10 information isformed on the charged photoconductor by the exposing unit 40. At thistime, the pixel counter 127 a starts counting the number of pixels thatare input to the exposing unit 40.

<Step of Moving Yellow Developing Unit (Step 5)>

The rotary 55 is rotated, and the yellow developing unit 54 is moved tothe developing position.

<Step of Starting Application of Yellow Developing Bias (Step 7)>

Application of a developing bias to the developing roller of the yellowdeveloping unit 54 is started. Thus, the latent image formed on thephotoconductor 20 is developed by yellow toner. The developing bias thatis applied is a voltage 25 obtained by superimposing an AC voltage and aDC voltage, as mentioned above. It should be noted that the developingbias may be applied to the developing roller before the yellowdeveloping unit 54 arrives at the developing position, or the developingbias may be applied to the developing roller 30 after the yellowdeveloping unit 54 arrives at the developing position.

<Step of Ending Application of Yellow Developing Bias (Step 9)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the yellow developing unit 54 is ended. Thus, theoperation of developing with the yellow developing unit 54 is ended.

<Step of Obtaining Number of Yellow Pixels (Step 11)>

The number of pixels that have been counted is obtained from the pixelcounter 127 a. The number of counted pixels is proportional to theamount of consumption of toner, and thus the amount of consumption ofyellow toner YT can be found.

<Step of Reading and Storing Yellow Toner Remaining Amount (Step 13)>

The remaining amount of yellow toner YY that is stored in the RAM isread out from the RAM, and a value YYnew obtained by subtracting theconsumption amount YT from the remaining amount YY is stored in the RAMas the new remaining amount.

<Step of Starting Movement of Cyan Developing Unit (Step 15)>

The rotary 55 starts rotating so as to position the cyan developing unit51 at the developing position.

<Step of Writing Information into Element 54 a (Step 17)>

The value YY new obtained by subtracting the consumption amount YT fromthe remaining amount YY is written into the element 54 a of the yellowdeveloping unit 54. This writing is carried out using the printer-sideantenna 124 b, without it being in contact with the element 54 a whichis moving. It should be noted that when this writing is carried out, theyellow developing unit 54 has not reached the detaching position (theattach/detach position) where it can be detached via the attach/detachopening 10 e.

<Step of Starting Counting Number of Cyan Pixels (Step 19)>

A latent image that corresponds to the cyan image information is formedon the charged photoconductor by the exposing unit 40. At this time, thepixel counter 127 a starts counting the number of pixels that are inputto the exposing unit 40.

<Step of Ending Movement of Cyan Developing Unit (Step 21)>

The rotation of the rotary 55 for positioning the cyan developing unit51 at the developing position is ended. Thus, the cyan developing unit51 arrives at the developing position.

<Step of Starting Application of Cyan Developing Bias (Step 23)>

Application of a developing bias tot he developing roller of the cyandeveloping unit 51 is started. Thus, the latent image formed on thephotoconductor 20 is developed by cyan toner.

<Step of Ending Application of Cyan Developing Bias (Step 25)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the cyan developing unit 51 is ended. Thus, theoperation of developing with the cyan developing unit 51 is ended.

<Step of Obtaining Number of Cyan Pixels (Step 26)>

The number of pixels that have been counted is obtained from the pixelcounter 127 a. The number of counted pixels is proportional to theamount of consumption of toner, and thus the amount of consumption ofcyan toner CT can be found.

<Step of Reading and Storing Cyan Toner Remaining Amount (Step 27)>

The remaining amount of cyan toner CC that is stored in the RAM is readout from the RAM, and a value CCnew obtained by subtracting theconsumption amount CT from the remaining amount CC is stored in the RAMas the new remaining amount.

<Step of Starting Movement of Magenta Developing Unit (Step 29)>

The rotary 55 starts rotating so as to position the magenta developingunit 52 at the developing position.

<Step of Writing Information into Element 51 a (Step 31)>

The value CCnew obtained by subtracting the consumption amount CT fromthe remaining amount CC is written into the element 51 a of the cyandeveloping unit 51. This writing is carried out using the printer-sideantenna 124 b, without it being in contact with the element 51 a whichis moving. It should be noted that when this writing is carried out, thecyan developing unit 51 has not reached the detaching position (theattach/detach position) where it can be detached via the attach/detachopening 10 e.

<Step of Starting Counting Number of Magenta Pixels (Step 33)>

A latent image that corresponds to the magenta image information isformed on the charged photoconductor by the exposing unit 40. At thistime, the pixel counter 127 a starts counting the number of pixels thatare input to the exposing unit 40.

<Step of Ending Movement of Magenta Developing Unit (Step 35)>

The rotation of the rotary 55 for positioning the magenta developingunit 52 at the developing position is ended. Thus, the magentadeveloping unit 52 arrives at the developing position.

<Step of Starting Application of Magenta Developing Bias (Step 37)>

Application of a developing bias to the developing roller of the magentadeveloping unit 52 is started. Thus, the latent image formed on thephotoconductor 20 is developed by magenta toner.

<Step of Ending Application of Magenta Developing Bias (Step 39)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the magenta developing unit 52 is ended. Thus, theoperation of developing with the magenta developing unit 52 is ended.

<Step of Obtaining Number of Magenta Pixels (Step 41)>

The number of pixels that have been counted is obtained from the pixelcounter 127 a. The number of counted pixels is proportional to theamount of consumption of toner, and thus the amount of consumption ofmagenta toner MT can be found.

<Step of Reading and Storing Magenta Toner Remaining Amount (Step 43)>

The remaining amount of magenta toner MM that is stored in the RAM isread out from the RAM, and a value MMnew obtained by subtracting theconsumption amount MT from the remaining amount MM is stored in the RAMas the new remaining amount.

<Step of Starting Movement of Black Developing Unit (Step 45)>

The rotary 55 starts rotating so as to position the black developingunit 53 at the developing position.

<Step of Writing Information into Element 52 a (Step 47)>

The value MMnew obtained by subtracting the consumption amount MT fromthe remaining amount MM is written into the element 52 a of the magentadeveloping unit 52. This writing is carried out using the printer-sideantenna 124 b, without it being in contact with the element 52 a whichis moving. It should be noted that when this writing is carried out, themagenta developing unit 52 has not reached the detaching position (theattach/detach position) where it can be detached via the attach/detachopening 10 e.

<Step-of Starting Counting Number of Black Pixels (Step 49)>

A latent image that corresponds to the black image information is formedon the charged photoconductor by the exposing unit 40. At this time, thepixel counter 127 a starts counting the number of pixels that are inputto the exposing unit 40.

<Step of Ending Movement of Black Developing Unit (Step 51)>

The rotation of the rotary 55 for positioning the black developing unit53 at the developing position is ended. Thus, the black developing unit53 arrives at the developing position.

<Step of Starting Application of Black Developing Bias (Step 53)>

Application of a developing bias to the developing roller of the blackdeveloping unit 53 is started. Thus, the latent image formed on thephotoconductor 20 is developed by black toner.

<Step of Ending Application of Black Developing Bias (Step 55)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the black developing unit 53 is ended. Thus, theoperation of developing with the black developing unit 53 is ended.

<Step of Obtaining Number of Black Pixels (Step 57)>

The number of pixels that have been counted is obtained from the pixelcounter 127 a. The number of counted pixels is proportional to theamount of consumption of toner, and thus the amount of consumption ofblack toner BT can be found.

<Step of Reading and Storing Black Toner Remaining Amount (Step 59)>

The remaining amount of black toner BB that is stored in the RAM is readout from the RAM, and a value BBnew obtained by subtracting theconsumption amount BT from the remaining amount BB is stored in the RAMas the new remaining amount.

<Step of Starting Movement to Home Position (Step 61)>

Rotation of the rotary 55 is started so as to position the rotary 55 atthe home position.

<Step of Writing Information into Element 53 a (Step 63)>

The value BBnew obtained by subtracting the consumption amount BT fromthe remaining amount BB is written into the element 53 a of the blackdeveloping unit 53. This writing is carried out using the printer-sideantenna 124 b, without it being in contact with the element 53 a whichis moving. It should be noted that when this writing is carried out, theblack developing unit 53 has not reached the detaching position (theattach/detach position) where it can be detached via the attach/detachopening 10 e.

<Step of Ending Printing Operation (Step 65)>

When the rotary 55 arrives at the home position, the image formingprocess is ended, and the printer enters the image forming processstandby state.

As described above, during the period from the start to the end of theimage forming process, the printer-side antenna 124 b, which serves asthe writing member, writes information into the element of each of thedeveloping units when the AC voltage supply section 126 a is notsupplying an AC voltage to the developing roller. Consequently,information can be written accurately without being affected by, forexample, noise caused by supplying the AC voltage.

Further, in the example described above, information is written into theelements by the printer-side antenna 124 b during the period from whenthe developing unit starts moving from the developing unit until itarrives at the attach/detach position due to the movement of the movingbody 55. Therefore, information can be effectively written using theperiod of time from when the unit starts moving from the developingposition until when the unit arrives at the attach/detach position.

It should be noted that the information written into the elements is notlimited to the remaining amount of toner. For example, it may also bethe usage amount of toner, and moreover, it may also be, for example,the developing time or the number of sheets developed.

<<Detailed Description of the Writing Timing>>

The flowchart shown in FIG. 10 is only one example. The process may befreely modified as long as it is possible for the printer-side antenna124 b, which serves as a writing member, to write information into theelement of each of the developing units when the AC voltage supplysection 126 a is not supplying an AC voltage to the developing rollerduring the period from the start to the end of the image formingprocess. For example, the step of writing information into the elementmay be performed before the step of starting movement of the developingunit. Moreover, it is also possible to perform the step of writinginformation into the element during the step of reading and storing thetoner remaining amount.

Further, considering the relationship with the developing unitattach/detach opening 10 e, the following writing timing is preferable.

In general, there is a possibility that the developing unit, forexample, the yellow developing unit 54, attached to the attach/detachsection may carelessly be detached via the attach/detach opening 10 e.In particular, since the amount of developer in the yellow developingunit 54 decreases when the yellow developing unit 54 is positioned atthe developing position and development is carried out, if the yellowdeveloping unit 54 is detached before information about the amount ofdeveloper that has decreased is written into the element 54 a, thenthere is a possibility that the amount of developer contained in theyellow developing unit 54, for example, cannot be ascertained.

Consequently, it is preferable that information is written into theelement 54 a during the period from when the yellow developing unit 54arrives at the developing position (see FIG. 9A) until when it arrivesat the attach/detach position (see FIG. 9B) due to movement of therotary 55, which serves as the moving body. Thus, for example, even ifthe yellow developing unit 54 is detached via the attach/detach opening10 e, information, such as the amount of developer contained in theyellow developing unit 54, will be written with accuracy without beingaffected by noise caused by supplying the AC voltage, for example.

It is even more preferable that the printer-side antenna 124 b writesinformation into the element 54 a of the yellow developing unit 54during the period from when the developing roller 510 provided in theyellow developing unit 54 that has arrived at the developing positionends developing the latent image until when the yellow developing unit54 arrives at the attach/detach position.

Further, in the example described above, after the yellow developingunit 54 started moving from the developing position, the yellowdeveloping unit 54 first arrived at the attach/detach position to andfrom which it can be attached and detached, and then the cyan developingunit 51, which is upstream in the direction of rotation, arrived at thedeveloping position with the further rotation of the rotary 55. However,it is also possible that, after the yellow developing unit 54 hasstarted moving from the developing position, the cyan developing unit51, which is upstream in the direction of rotation, first arrives at thedeveloping position and then the yellow developing unit 54 arrives atthe attach/detach position, where it can be attached and detached, withthe further rotation of the rotary 55.

If, during the period from when the developing unit starts moving fromthe developing position until when it arrives at the attach/detachposition, another developing unit adjacent to this developing unit onthe upstream side therefrom in the direction of rotation of the rotaryarrives at the developing position as described above, then it ispreferable that the printer-side antenna 124 b writes information intothe element of this developing unit during the period until the otherdeveloping unit arrives at the developing position. Since theprinter-side antenna 124 b writes information into the element of thisdeveloping unit during the period until the other developing unitarrives at the developing position, information would already be writteninto the element, even if, for example, this developing unit is forciblydetached after the other developing unit arrives at the developingposition.

The above-mentioned detailed description of the writing timing for theyellow developing unit 54 can be similarly adopted for the developingunits of the other colors as well.

Writing Information into Element of Photoconductor Unit

Next, the writing of information into the element 75 a of thephotoconductor unit 75 is described with reference to FIG. 11. FIG. 11is a flowchart showing an example in which information is written intothe element 75 a of the photoconductor unit 75.

<Step of Standby for Image Forming Process (Step 101)>

When the printer 10 is turned ON, a predetermined initializationoperation is performed, and the printer 10 enters an image formingprocess standby state. When an image signal, which is an image formingprocess command from the host computer, is input to the main controller101 of the printer 10 via the interface (I/F) 112, the photoconductor 20and the intermediate transferring body 70 are rotated. Then, the readsensor for synchronization RS detects the reference position of theintermediate transferring body 70 and outputs a pulse signal. The unitcontroller 102 executes the following control, taking the pulse signalthat has been received as a reference.

<Step of Starting Movement of Yellow Developing Unit (Step 103)>

The rotary 55 starts rotating so as to position the yellow developingunit 54 at the developing position.

<Step of Ending Movement of Yellow Developing Unit (Step 105)>

The rotation of the rotary 55 for positioning the yellow developing unit54 at the developing position is ended. Thus, the yellow developing unit54 arrives at the developing position.

<Step of Starting Application of Yellow Developing Bias (Step 107)>

Application of a developing bias to the developing roller of the yellowdeveloping unit 54 is started. Thus, the latent image formed on thephotoconductor 20 is developed by yellow toner. The developing bias thatis applied is a voltage obtained by superimposing an AC voltage and a DCvoltage, as mentioned above. It should be noted that the developing biasmay be applied to the developing roller before the yellow developingunit 54 arrives at the developing position, or the developing bias maybe applied to the developing roller after the yellow developing unit 54arrives at the developing position.

<Step of Ending Application of Yellow Developing Bias (Step 109)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the yellow developing unit 54 is ended. Thus, theoperation of developing with the yellow developing unit 54 is ended.

<Step of Starting Movement of Cyan Developing Unit (Step 111)>

The rotary 55 starts rotating so as to position the cyan developing unit51 at the developing position.

<Step of Ending Movement of Cyan Developing Unit (Step 113)>

The rotation of the rotary 55 for positioning the cyan developing unit51 at the developing position is ended. Thus, the cyan developing unit51 arrives at the developing position.

<Step of Starting Application of Cyan Developing Bias (Step 115)>

Application of a developing bias to the developing roller of the cyandeveloping unit 51 is started. Thus, the latent image formed on thephotoconductor 20 is developed by cyan toner.

<Step of Ending Application of Cyan Developing Bias (Step 117)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the cyan developing unit 51 is ended. Thus, theoperation of developing with the cyan developing unit 51 is ended.

<Step of Starting Movement of Magenta Developing Unit (Step 119)>

The rotary 55 starts rotating so as to position the magenta developingunit 52 at the developing position.

<Step of Ending Movement of Magenta Developing Unit (Step 121)>

The rotation of the rotary 55 for positioning the magenta developingunit 52 at the developing position is ended. Thus, the magentadeveloping unit 52 arrives at the developing position.

<Step of Starting Application of Magenta Developing Bias (Step 123)>

Application of a developing bias to the developing roller of the magentadeveloping unit 52 is started. Thus, the latent image formed on thephotoconductor 20 is developed by magenta toner.

<Step of Ending Application of Magenta Developing Bias (Step 125)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the magenta developing unit 52 is ended. Thus, theoperation of developing with the magenta developing unit 52 is ended.

<Step of Starting Movement of Black Developing Unit (Step 127)>

The rotary 55 starts rotating so as to position the black developingunit 53.at the developing position.

<Step of Ending Movement of Black Developing Unit (Step 129)>

The rotation of the rotary 55 for positioning the black developing unit53 at the developing position is ended. Thus, the black developing unit53 arrives at the developing position.

<Step of Starting Application of Black Developing Bias (Step 131)>

Application of a developing bias to the developing roller of the blackdeveloping unit 53 is started. Thus, the latent image formed on thephotoconductor 20 is developed by black toner.

<Step of Ending Application of Black Developing Bias (Step 133)>

At a predetermined timing, application of the developing bias to thedeveloping roller of the black developing unit 53 is ended. Thus, theoperation of developing with the black developing unit 53 is ended.

<Step of Writing Information into Element 75 a (Step 135)>

Information indicating the number of sheets printed in color is writteninto the element 75 a of the photoconductor unit 75 using theprinter-side antenna 124 a. The number of sheets printed in color may bethe total number of sheets printed in color by the printer 10, or it maybe the number of sheets for which color printing has been performedusing the photoconductor unit 75 after the photoconductor unit 75 wasattached to the printer unit 10 a.

<Step of Determining the Presence of Print Data (Step 137)>

Whether or not there are further data to be printed is determined, andif there are print data, then the procedure proceeds to the <Step ofStarting Movement of Yellow Developing Unit (Step 103)>.

<Step of Starting Movement to Home Position (Step 139)>

If there are print data, then rotation of the rotary 55 is started so asto position it at the home position.

<Step of Ending Printing Operation (Step 141)>

When the rotary 55 arrives at the home position, the image formingprocess is ended, and the printer enters the image forming processstandby state.

As described above, during the period from the start to the end of theimage forming process, the printer-side antenna 124 a, which serves asthe writing member, writes information into the element 75 a of thephotoconductor unit 75 when the AC voltage supply section 126 a is notsupplying an AC voltage to a developing roller. Consequently,information can be written accurately without being affected by, forexample, noise caused by supplying the AC voltage.

It should be noted that the information written into the element 75 a isnot limited to the number of sheets printed in color. For example, asshown in FIG. 8, it can also be the number of sheets printed when usagestarts, the number of sheets printed when usage ends, or the number ofsheets printed in monochrome.

It may also be information about, for example, the remaining amount orthe usage amount of toner of each of the developing units. In this case,for example, in place of the step of writing information into theelement of each of the developing units in FIG. 10, it is possible toprovide a step of writing information into the element 75 a of thephotoconductor unit 75.

Further, as regards the relationship between the developing unit 54 andthe attach/detach opening 10 e, it is preferable that the printer-sideantenna 124 a writes information into the element 75 a of thephotoconductor unit 75 during the period from when the developing unitarrives at the developing position until when it arrives at thedetaching position due to movement of the rotary 55.

Further, if, during the period from when the developing unit startsmoving from the developing position until when it arrives at thedetaching position, another developing unit adjacent to this developingunit on the upstream side there from in the direction of movement of therotary 55 arrives at the developing position, then it is preferable thatthe printer-side antenna 124 a writes information into the element 75 aof the photoconductor unit 75 during the period until the otherdeveloping unit arrives at the developing position.

Other Embodiments of the First Embodiment

In the foregoing, developing units according to the present inventionwere described according to a first embodiment thereof. However, theforegoing embodiment of the invention is for the purpose of facilitatingunderstanding of the present invention and is not to be interpreted aslimiting the present invention. The present invention can be altered andimproved without departing from the gist thereof, and needless to say,the present invention includes its equivalents.

<Another Example of AC Voltage Application>

It is also possible to adopt a configuration in which the AC voltagesupply section 126 a supplies an AC voltage to the charging unit 30 viathe charging unit drive circuit so that the charging unit 30 charges thephotoconductor 20 in an alternating electric field. In this case, duringthe period from the start to the end of the image forming process, theprinter-side antenna 124 b can write information into the element of thedeveloping unit attached to the attach/detach section when the ACvoltage supply section 126 a is not supplying an AC voltage to thecharging unit 30. Thus, information can be written accurately withoutbeing affected by, for example, noise caused by supplying the AC voltageto the charging unit 30.

It is also possible to adopt a configuration in which the AC voltagesupply section 126 a supplies an AC voltage to the first transferringunit 60 via the first transferring unit drive circuit. In this case,during the period from the start to the end of the image formingprocess, the printer-side antenna 124 b can write information into theelement of the developing unit attached to the attach/detach sectionwhen the AC voltage supply section 126 a is not supplying an AC voltageto the first transferring unit 60. Thus, information can be writtenaccurately without being affected by, for example, noise caused bysupplying the AC voltage to the first transferring unit 60.

<Intensity of the AC Voltage>

The present embodiment is particularly effective in image formingprocessing in which there is a large difference between the maximumvoltage value and the minimum voltage value applied by the AC voltagesupply section 126 a. For example, it is particularly effective in imageforming apparatuses in which the difference between the maximum voltagevalue and the minimum voltage value is 1000 volts or more. When thedifference between the maximum voltage value and the minimum voltagevalue of the AC voltage is 1000 volts or more, the electromagnetic noisethat occurs also becomes large. In such image forming apparatuses, bywriting information with the writing member into the element of adeveloping unit that is attached to the attach/detach section when theAC voltage supply section 126 a is not supplying an AC voltage duringthe period from the start to the end of the image forming process, itbecomes possible to accurately write information without being affectedby, for example, the large amount of noise that is caused by supplyingthe AC voltage.

<Developing Unit>

The developing unit is not limited to a device of the configurationdescribed in the foregoing embodiment, and it is applicable to any typeof developing unit. The developing unit may be of any configuration aslong as it has an element into which information can be written and adeveloper containing section. For example, the developing unit does nothave to include a developer bearing body, and the developing unit may beprovided in the printer unit 10 a.

For example, it is possible to use any material as the developer bearingroller, such as magnetic material, non-magnetic material, conductivematerial, insulating material, metal, rubber, and resin, as long as itis possible to structure a developer bearing roller. For example, as thematerial, it is possible to use: metal such as aluminum, nickel,stainless steel, and iron; rubber such as natural rubber, siliconerubber, urethane rubber, butadiene rubber, chloroprene rubber, neoprenerubber, and NBR; or resin such as styrene resin, vinyl chloride resin,polyurethane resin, polyethylene resin, methacrylate resin, and nylonresin. Further, it is without saying that these can be used even if theupper layer of these materials is coated. In this case, as the coatingmaterial, it is possible to use, for example, polyethylene, polystyrene,polyurethane, polyester, nylon, or acrylic resin. Further, it ispossible to use any form, such as an inelastic body, an elastic body, asingle-layer structure, a multi-layer structure, a film, and a roller.Further, the developer is not limited to toner, but it may be, forexample, a two component developer in which a carrier is mixed.

Further, the same applies for the toner supplying member as well, and asthe material therefor, other than polyurethane foam described above, itis possible to use, for example, polystyrene foam, polyethylene foam,polyester foam, ethylene propylene foam, nylon foam, or silicone foam.It should be noted that, as the foam cells of the toner supplying means,both open-cell foams and closed-cell foams can be used. It should benoted that there is no limitation to foam material, and it is possibleto use rubber material having elasticity. More specifically, it ispossible to use a material that is molded and in which a conductiveagent such as carbon is dispersed into, for example, silicone rubber,urethane rubber, natural rubber, isoprene rubber, styrene butadienerubber, butadiene rubber, chloroprene rubber, butyl rubber, ethylenepropylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, oracrylic rubber.

<Photoconductor Unit>

The photoconductor unit 75 also is not limited to the device of theconfiguration described in the foregoing embodiment, and it isapplicable to any type of device. It is only necessary that thephotoconductor unit 75 has an element into which information can bewritten and a photoconductor. For example, it does not have to includethe charging unit 30, and instead, the charging unit may be provided inthe printer unit 10 a. Further, the photoconductor is not limited to aroller-shaped photoconductive roller, and it may also be belt-shaped.

<Elements>

The elements of the developing units and the element of thephotoconductor unit are not limited to the configuration described inthe foregoing embodiment. It is only necessary that information can bewritten into them, and it is possible for them to be, for example,elements in which the antenna is provided separately.

<Image Forming Apparatus>

In the foregoing embodiment, an intermediate transferring typefull-color laser beam printer was described as an example of the imageforming apparatus, but the present invention is also applicable tovarious other types of image forming apparatuses, such as full-colorlaser beam printers that are not of the intermediate transferring type,monochrome laser beam printers, copying machines, and facsimiles.

Configuration of Computer System Etc.

Next, an embodiment of a computer system, a computer program, and astorage medium on which the computer program is recorded, which serve asan example of an embodiment of the present invention, is described withreference to the drawings.

FIG. 12 is an explanatory drawing showing an external structure of acomputer system. The computer system 1000 comprises a computer unit1102, a display device 1104, a printer 1106, an input device 1108, and areading device 1110. In this embodiment, the computer unit 1102 isaccommodated in a mini-tower type housing, but this is not a limitation.A CRT (cathode ray tube), a plasma display, or a liquid crystal displaydevice, for example, is generally used as the display device 1104, butthis is not a limitation. The printer described above is used as theprinter 1106. In this embodiment, a keyboard 1108A and a mouse 1108B areused as the input device 1108, but this is not a limitation. In thisembodiment, a flexible disk drive device 1110A and a CD-ROM drive device1110B are used as the reading device 1110, but the reading device is notlimited to these, and it may also be other devices such as a MO (magnetooptical) disk drive device and a DVD (digital versatile disk).

FIG. 13 is a block diagram showing a configuration of the computersystem shown in FIG. 12. Further provided are an internal memory 1202,such as a RAM inside the housing accommodating the computer unit 1102,and an external memory such as a hard disk drive unit 1204.

It should be noted that in the above description, an example in whichthe computer system is structured by connecting the printer 1106 to thecomputer unit 1102, the display device 1104, the input device 1108, andthe reading device 1110 was described, but this is not a limitation. Forexample, the computer system can be made of the computer unit 1102 andthe printer 1106, or the computer system does not have to comprise anyone of the display device 1104, the input device 1108, and the readingdevice 1110.

Further, for example, the printer 1106 can have some of the functions ormechanisms of the computer unit 1102, the display device 1104, the inputdevice 1108, and the reading device 1110. As an example, the printer1106 may be configured so as to have an image processing section forcarrying out image processing, a displaying section for carrying outvarious types of displays, and a recording media attach/detach sectionto and from which recording media storing image data captured by adigital camera or the like are inserted and taken out.

As an overall system, the computer system that is achieved in this waybecomes superior to conventional systems.

SECOND EMBODIMENT

In the second embodiment, the arrangement of the element (2051 a, 2052a, 2053 a, 2054 a) of each of the developing units is different from thefirst embodiment. The second embodiment is described below centering onfeatures that are different from those of the first embodiment, andstructures and processes of sections for which no particular descriptionis given are the same as those of the first embodiment. Further,structures and processes, for example, having the same referencecharacters as those in the first embodiment are the same as those in thefirst embodiment.

Overview of Developing Units

Next, an overview of the developing units is described using FIG. 14 andFIG. 15. FIG. 14 is a perspective view of the yellow developing unit2054 seen from the side of a developing roller 2510. FIG. 15 is across-sectional view showing main structural components of the yellowdeveloping unit 2054. It should be noted that in FIG. 15 as well, theup/down direction is shown by an arrow, and for example, the centralaxis of the developing roller 2510 is located lower than the centralaxis of the photoconductor 20. Further, in FIG. 15, the yellowdeveloping unit 2054 is shown in a state in which it is positioned at adeveloping position that is in opposition to the photoconductor 20.

The YMCK developing device 50 is provided with the cyan developing unit2051, which contains cyan (C) toner, the magenta developing unit 2052,which contains magenta (M) toner, the black developing unit 2053, whichcontains black (K) toner, and the yellow developing unit 2054, whichcontains yellow (Y) toner. Since the configuration of each of thesedeveloping units is the same, the yellow developing unit 2054 isdescribed below.

The yellow developing unit 2054 is provided with, for example, adeveloper containing section, that is, a first containing section 2530and a second containing section 2535 for containing yellow toner T whichserves as the developer, an element 2054 a, a housing 2540 for formingthe developer containing section, the developing roller 2510 whichserves as the developer bearing body, a toner supply roller 2550 forsupplying toner T to the developing roller 2510, and a restriction blade2560 for restricting the thickness of the layer of toner T that is boreon the developing roller 2510.

The housing 2540 is manufactured by joining, for example, an upperhousing and a lower housing which have been integrally molded, and theinside of the housing is divided into the first containing section 2530and the second containing section 2535 by a restriction wall 2545 thatextends upward from the lower section (in the up/down direction of FIG.15). The first containing section 2530 and the second containing section2535 form developer containing sections (2530, 2535) for containingtoner T which serves as a developer. The upper sections of the firstcontaining section 2530 and the second containing section 2535 are incommunication, and the movement of the toner T between them isrestricted by the restriction wall 2545. It should be noted that it isalso possible to provide a stirring member for stirring the toner Tcontained in the first containing section 2530 and the second containingsection 2535. In the present embodiment, however, each of the developingunits (the cyan developing unit 2051, the magenta developing unit 2052,the black developing unit 2053, and the yellow developing unit 2054)rotates in conjunction with the rotation of the rotary 55 so that thetoner T in each developing unit is stirred. Therefore, a stirring memberis not provided in the first containing section 2530 or the secondcontaining section 2535.

The element 2054 a is provided on the outer surface of the housing 2540.The element 2054 a has a configuration that allows storage ofinformation that has been written in.

An opening 2541 that communicates with the outside of the housing 2540is provided in the lower section of the first containing section 2530.The toner supply roller 2550 is provided in the first containing section2530 with its circumferential surface facing the opening 2541, and isrotatably supported on the housing 2540. Further, the developing roller2510 is provided with its circumferential surface facing the opening2541 from outside the housing 2540, and the developing roller 2510 abutsagainst the toner supply roller 2550.

The developing roller 2510 bears toner T and carries the toner to adeveloping position, which is in opposition to the photoconductor 20.The developing roller 2510 is made of, for example, aluminum, stainlesssteel, or iron, and if necessary, it can be subjected to nickel platingor chromium plating, and the toner bearing region can be subjected tosandblasting or the like. Further, the developing roller 2510 isprovided such that its longitudinal direction is in the longitudinaldirection of the yellow developing unit 2054.

Further, the developing roller 2510 has a rotating shaft 2512 and largediameter section 2514 whose diameter is greater than the diameter of therotating shaft 2512 and which is for bearing the developer. Thedeveloping roller 2510 can rotate about the rotating shaft 2512, and asshown in FIG. 15, it rotates in the opposite direction (in FIG. 15, thecounterclockwise direction) to the rotating direction of thephotoconductor 20 (in FIG. 15, the clockwise direction). The rotatingshaft 2512 is located lower than the central axis of the photoconductor20. Further, as shown in FIG. 15, in a state in which the yellowdeveloping unit 2054 is in opposition to the photoconductor 20, a gapexists between the developing roller 2510 and the photoconductor 20.That is, the yellow developing unit 2054 develops the latent imageformed on the photoconductor 20 in a non-contacting state. It should benoted that the rotating shaft 2512 and the large diameter section 2514are conductive, and when the latent image formed on the photoconductor20 is developed, a voltage obtained by superimposing an AC voltage and aDC voltage, as mentioned above, is applied to the rotating shaft 2512and the large diameter section 2514, and thus, an alternating electricfield is formed between the developing roller 2510 and thephotoconductor 20.

Further, the above-mentioned element 2054 a is provided on the outersurface of the housing 2540 at a position more to the outside than thelarge diameter section 2514 in the axial direction of the rotating shaft2512. As long as the element 2054 a is positioned more to the outsidethan the large diameter section 2514 in the axial direction of therotating shaft 2512, it can be provided either upstream or downstream inthe axial direction of the developing roller 2510. In the presentembodiment, however, if the direction shown in FIG. 14 is taken as theaxial direction, then the element is provided upstream in this axialdirection.

The toner supply roller 2550 supplies, to the developing roller 2510,the toner T contained in the first containing section 2530 and thesecond containing section 2535. The toner supply roller 2550 is made ofpolyurethane foam, for example, and abuts against the developing roller2510 in a state in which it is elastically deformed. The toner supplyroller 2550 is arranged at a lower section of the first containingsection 2530, and the toner T contained in the first containing section2530 and the second containing section is supplied to the developingroller 2510 by the toner supply roller 2550 at the lower section of thefirst containing section 2530. The toner supply roller 2550 can rotateabout its central axis, and its central axis is located lower than thecentral rotating shaft of the developing roller 2510. Further, the tonersupply roller 2550 rotates in the opposite direction (in FIG. 15, theclockwise direction) to the rotating direction of the developing roller2510 (in FIG. 15, the counterclockwise direction). It should be notedthat the toner supply roller 2550 has the function of supplying thetoner T that is contained in the first containing section 2530 and thesecond containing section 2535 to the developing roller 2510 as well asthe function of stripping off, from the developing roller 2510, thetoner T that remains on the developing roller 2510 after development.

The restriction blade 2560 restricts the thickness of the toner T layerbore by the developing roller 2510, and gives charge to the toner T boreby the developing roller 2510. The restriction blade 2560 has a rubbersection 2560 a and a rubber support section 2560 b. The rubber section2560 a is made of, for example, silicone rubber or urethane rubber, andthe rubber support section 2560 b is a thin plate made of, for example,phosphor bronze or stainless steel, and has a springy characteristic.The rubber section 2560 a is supported by the rubber support section2560 b, and one end of the rubber support section 2560 b is fixed to ablade support metal plate 2562. The blade support metal plate 2562 isfastened to a seal frame, and is attached to the housing 2540 togetherwith the restriction blade 2560, forming a part of a seal unit 2520,which is described later. In this state, the rubber section 2560 a ispressed against the developing roller 2510 by the elastic force createdby the flexure of the rubber support section 2560 b.

Further, a blade backing member 2570 made of Moltoprene or the like isprovided on one side of the restriction blade 2560 opposite from theside of developing roller 2510. The blade backing member 2570 preventsthe toner T from entering in between the rubber support section 2560 band the housing 2540 to stabilize the elastic force caused by theflexure of the rubber support section 2560 b, and also presses therubber section 2560 a against the developing roller 2510 by applyingforce to the rubber section 2560 a toward the developing roller 2510from directly behind the rubber section 2560 a. Consequently, the bladebacking member 2570 improves the contact uniformity and the sealingproperties of the rubber section 2560 a with respect to the developingroller 2510.

The end of the restriction blade 2560 on the side opposite from the sidesupported by the blade support metal plate 2562, that is, its tip, isnot in contact with the developing roller 2510; rather, a section at apredetermined distance from its tip contacts, with some breadth, thedeveloping roller 2510. That is, the restriction blade 2560 does notabut against the developing roller 2510 at its edge but rather at itsmid section. Further, the restriction blade 2560 is arranged such thatits tip is facing upstream in the rotating direction of the developingroller 2510, and thus, makes a so-called counter-abutment with respectto the roller. It should be noted that the abutting position where therestriction blade 2560 abuts against the developing roller 2510 islocated lower than the central axis of the developing roller 2510 and isalso located lower than the central axis of the toner supply roller2550.

The seal member 2520 prevents the toner T in the yellow developing unit2054 from spilling out from the unit, and also collects the toner T onthe developing roller 2510, which has passed the developing position,into the developing unit without scraping it off. The seal member 2520is a seal made of polyethylene film or the like. The seal member 2520 issupported by a seal support metal plate 2522, and is attached to theframe 2540 via the seal support metal plate 2522. A seal urging member2524 made of Moltoprene or the like is provided on one side of the sealmember 2520 opposite from the side of the developing roller 2510, anddue to the elastic force of the seal urging member 2524, the seal member2520 is pressed against the developing roller 2510. It should be notedthat the abutting position where the seal member 2520 abuts against thedeveloping roller 2510 is located above the central axis of thedeveloping roller 2510.

In the yellow developing unit 2054 configured in this manner, the tonersupply roller 2550 supplies, to the developing roller 2510, the toner Tthat is contained in the first containing section 2530 and the secondcontaining section 2535, which serve as developer containing sections.The toner T that is supplied to the developing roller 2510 is brought tothe abutting position of the restriction blade 2560 in conjunction withthe rotation of the developing roller 2510, and when it passes theabutting position, the thickness of the toner layer is restricted andthe toner is charged. Then, due to further rotation of the developingroller 2510, the toner T on the developing roller 2510, whose layerthickness has been restricted, is brought to the developing positionopposing the photoconductor 20, and is used for developing the latentimage formed on the photoconductor 20 under the alternating electricfield at the developing position. The toner T on the developing roller2510 that has passed the developing position due to further rotation ofthe developing roller 2510 passes the seal member 2520 and is collectedinto the developing unit by the seal member 2520 without being scrapedoff.

In this way, since the element is provided more to the outside than thelarge diameter section 2514 in the axial direction of the rotating shaft2512, it is possible to achieve accurate communication with thatelement.

That is, as discussed in the section on the problems to be solved by thepresent invention, it is necessary that communication between theelements and the printer unit 10 a is carried out accurately. Forexample, when writing information about the remaining amount of tonerinto the element of a developing unit, if a communication error occursand incorrect information is written, then the amount of toner remainingin the developing unit cannot be managed properly.

On the other hand, in a situation where an AC voltage supply section forsupplying an AC voltage is provided, there is a possibility thatelectromagnetic noise will be generated in the periphery of the ACvoltage supply section while it is supplying an AC voltage.

Accordingly, as discussed above, if the element is provided more to theoutside than the large diameter section 2514 in the axial direction ofthe rotating shaft 2512, then the distance between the element and thedeveloping roller 2510 becomes longer by the amount of difference indiameter between the rotating shaft 2512 and the large diameter section2514, compared to a case where, for example, the element is providedmore to the inside than the large diameter section 2514 in the axialdirection of the rotating shaft 2512. Therefore, even if theelectromagnetic noise is generated due to the application of an ACvoltage to the developing roller 2510, it becomes possible to reduce thenegative influence on communication due to that noise, and thus, itbecomes possible to achieve accurate communication with respect to theelement.

Relationship Between Element and Printer-side Antenna

Next, the relationship between the elements of the developing units andthe printer-side antenna 2124 b is described with reference to FIG. 16Ato FIG. 16C. FIG. 16A is a diagram for describing the relationshipbetween the element and the printer-side antenna when the yellowdeveloping unit 2054 is positioned at the developing position. FIG. 16Bis a diagram for describing the relationship between the element and theprinter-side antenna when the yellow developing unit 2054 is positionedat the attach/detach position. FIG. 16C is a diagram for describing therelationship between the element and the printer-side antenna when therotary 55 is positioned at the home position.

In FIG. 16A, the yellow developing unit 2054 is positioned at thedeveloping position (opposing position), and the element 2054 a of theyellow developing unit 2054 is in opposition to the printer-side antenna2124 b in a non-contact state. The printer-side antenna 2124 b, as shownin FIG. 16A, is provided so that the element 2054 a is positioned moreto the inside than the printer-side antenna 2124 b in the radialdirection of rotation of the rotary 55.

It should be noted that the element 2054 a is positioned more to theoutside than the body of the yellow developing unit in the radialdirection of rotation of the rotary 55.

Further, the printer-side antenna 2124 b can wirelessly communicate withthe element 2054 a not only when the rotary 55 is in a stopped state butalso when the rotary 55 is in a moving state. That is, the printer-sideantenna 2124 b can wirelessly communicate with the element 2054 a evenif the element is moving.

Rotation of Rotary 55 and Attach/Detach Position (Attaching andDetaching Position) of Developing Units

Next, the relationship between the rotation of the rotary 55 and theposition where the developing units are detached is described withreference again to FIG. 16A to FIG. 16C.

As described above, in the state shown in FIG. 16A, the yellowdeveloping unit 2054 is positioned at the developing position. When therotary 55 is rotated from this state by a predetermined angle in the Zdirection, the state shown in FIG. 16B is attained. In the state shownin FIG. 16B, the yellow developing unit 2054 is positioned at a positionwhere it can be attached and detached. In this state, the yellowdeveloping unit 2054 can be attached and detached via the attach/detachopening 10 e, that is, it can be mounted to the attach/detach section 55e or it can be removed from the attach/detach section 55 e. Then, whenthe rotary 55 is rotated from the state shown in FIG. 16B by apredetermined angle in the Z direction, the cyan developing unit 2051,which is positioned upstream in the direction of rotation of the rotary55, is positioned at the developing position.

It should be noted that FIG. 16C shows a state in which the rotary 55 ispositioned at the home position after the printer 10 has been turned ONand the initialization operation has been performed.

Further, the procedure for writing information into the element, forexample, is the same as that in the first embodiment, and thusdescription thereof is omitted here.

Other Embodiments of the Second Embodiment

In the foregoing, developing units according to the present inventionwere described according to a second embodiment thereof. However, theforegoing embodiment of the invention is for the purpose of facilitatingunderstanding of the present invention and is not to be interpreted aslimiting the present invention. The present invention can be altered andimproved without departing from the gist thereof, and needless to say,the present invention includes its equivalents.

In the foregoing embodiment, the rotating shaft and the large diametersection had conductivity, and it was possible to apply an AC voltage tothem. However, this is not a limitation.

In this case, however, the degree to which the electromagnetic noiseaffects communication is conspicuous. Therefore, the foregoingembodiment is more effective in terms that the above-described effects,that is, the effect that it becomes possible to reduce the negativeinfluence that the electromagnetic noise has on communication and theeffect that it becomes possible to achieve accurate communication withthe element are more effectively achieved.

Further, in the foregoing embodiment, the developing unit had a housingfor forming the developing roller, and the element was provided in thehousing, but this is not a limitation. For example, it is possible toprovide the element in another member other than the housing.

However, the configuration of the foregoing embodiment is preferablebecause it is possible to achieve a developing unit in which the elementis provided at an easily attachable position.

Further, in the foregoing embodiment, the element was positioned more tothe outside than the developing unit body, which includes the developercontaining sections, in the radial direction of rotation of the rotarywhen the developing unit has been attached to the attach/detach section.However, this is not a limitation.

However, the configuration of the foregoing embodiment is morepreferable in terms that, in such a case, it becomes even easier toattach the element because the element is arranged more to the outsidethan the developing unit body in the radial direction of rotation of therotary.

Further, in the foregoing embodiment, the element was positioned more tothe inside than the printer-side antenna (antenna for communicating withthe developing unit element) in the radial direction of rotation of therotary when the developing unit has been attached to the attach/detachsection. However, this is not a limitation.

However, the configuration of the foregoing embodiment is morepreferable in terms that, in such a case, it also becomes easy to attachthe printer-side antenna (antenna for communicating with the developingunit element) because the element is arranged more to the inside thanthe printer-side antenna (antenna for communicating with the developingunit element) in the radial direction of rotation of the rotary.

Further, in the foregoing embodiment, the printer wrote information intothe element of the developing unit attached to the attach/detach sectionusing the printer-side antenna during the period from when thedeveloping unit has arrived at the opposing position, where it is inopposition to the photoconductor, until when the developing unit hasarrived at the detaching position, where it can be detached from theattach/detach section-via the attach/detach opening, due to rotation ofthe rotary. However, this is not a limitation. For example, it is alsopossible to write information, at another timing, into the element ofthe developing unit that is attached to the attach/detach section usingthe printer-side antenna.

If, however, the image forming apparatus is provided with anattach/detach opening through which the developing unit is attached toand detached from the attach/detach section, then there is a possibilitythat a developing unit attached to the attach/detach section maycarelessly be detached via the attach/detach opening. In particular,since the amount of developer in the developing unit decreases when thedeveloping unit is positioned at the opposing position and developmentis carried out, if the developing unit is detached before informationabout the amount of developer that has decreased is written into itselement, then it may not be possible to ascertain the amount ofdeveloper contained in the developing unit, for example. For thisreason, the configuration of the foregoing embodiment is more preferablein terms that it can solve this problem.

Further, in the foregoing embodiment, the printer comprised an ACvoltage supply section for supplying an AC voltage, and the printerwrote information into the element of the developing unit attached tothe attach/detach section using the antenna when the AC voltage supplysection is not supplying an AC voltage to the developing roller.However, it is also possible for the printer to write information intothe element of the developing unit attached to the attach/detach sectionusing the antenna when the AC voltage supply section is supplying an ACvoltage to the developing roller.

In such a case, there is an increased possibility that theelectromagnetic noise will negatively affect communication becauseinformation is written into the element when the AC voltage supplysection is supplying an AC voltage to the developing roller. Therefore,the above-described effects, that is, the effect that it becomespossible to reduce the negative influence that the electromagnetic noisehas on communication and the effect that it becomes possible to achieveaccurate communication with the element are more effectively achieved.

It is also possible for the difference between the maximum voltage valueand the minimum voltage value of the AC voltage to be 1000 volts ormore.

When the difference between the maximum voltage value and the minimumvoltage value of the AC voltage is 1000 volts or more, theelectromagnetic noise that is generated also becomes large, andtherefore, the above-described effects, that is, the effect that itbecomes possible to reduce the negative influence that theelectromagnetic noise has on communication and the effect that itbecomes possible to achieve accurate communication with the element aremore effectively achieved.

Further, in the foregoing embodiment, the printer-side antenna (antennafor communicating with the developing unit element) was capable ofcommunicating with the element in a non-contact state with respect tothe element. However, this is not a limitation.

However, the configuration of the foregoing embodiment is more effectivein terms that, in such a case, since the environment pertaining to thecommunication between the element and the printer-side antenna (antennafor communicating with the developing unit element) is severe comparedto a case where, for example, communication is carried out in a state inwhich they are in contact with each other, the above-described effects,that is, the effect that it becomes possible to reduce the negativeinfluence that the electromagnetic noise has on communication and theeffect that it becomes possible to achieve accurate communication withthe element are more effectively achieved.

<Photoconductor Unit>

The photoconductor unit 75 is not limited to the device of theconfiguration described in the foregoing embodiment, and it isapplicable to any type of device. It is only necessary that thephotoconductor unit 75 has an element into which information can bewritten and a photoconductor. For example, it does not have to includethe charging unit 30, and instead, the charging unit may be provided inthe printer unit 10 a. Further, the photoconductor is not limited to aroller-shaped photoconductive roller, and it may also be belt-shaped.

<Developing Roller Etc.>

It is possible to use any material as the developer roller, such asmagnetic material, non-magnetic material, conductive material,insulating material, metal, rubber, and resin, as long as it is possibleto structure a developer roller. For example, as the material, it ispossible to use: metal such as aluminum, nickel, stainless steel, andiron; rubber such as natural rubber, silicone rubber, urethane rubber,butadiene rubber, chloroprene rubber, neoprene rubber, and NBR; or resinsuch as styrene resin, vinyl chloride resin, polyurethane resin,polyethylene resin, methacrylate resin, and nylon resin. Further, it iswithout saying that these can be used even if the upper layer of thesematerials is coated. In this case, as the coating material, it ispossible to use, for example, polyethylene, polystyrene, polyurethane,polyester, nylon, or acrylic resin. Further, it is possible to use anyform, such as an inelastic body, an elastic body, a single-layerstructure, a multi-layer structure, a film, and a roller. Further, thedeveloper is not limited to toner, but it may be, for example, a twocomponent developer in which a carrier is mixed. It should be noted thatas regards the conductivity and insulation properties of the developingroller, it is preferable that the developing roller is conductive, asmentioned above.

Further, the same applies for the toner supplying member as well, and asthe material therefor, other than polyurethane foam described above, itis possible to use, for example, polystyrene foam, polyethylene foam,polyester foam, ethylene propylene foam, nylon foam, or silicone foam.It should be noted that, as the foam cells of the toner supplying means,both open-cell foams and closed-cell foams can be used. It should benoted that there is no limitation to foam material, and it is possibleto use rubber material having elasticity. More specifically, it ispossible to use a material that is molded and in which a conductiveagent such as carbon is dispersed into, for example, silicone rubber,urethane rubber, natural rubber, isoprene rubber, styrene butadienerubber, butadiene rubber, chloroprene rubber, butyl rubber, ethylenepropylene rubber, epichlorohydrin rubber, nitrile butadiene rubber, oracrylic rubber.

<Elements>

The elements of the developing units and the element of thephotoconductor unit are not limited to the configuration described inthe foregoing embodiment. It is only necessary that information can bewritten into them, and it is possible for them to be, for example,elements in which the antenna is provided separately.

<Image Forming Apparatus>

In the foregoing embodiment, an intermediate transferring typefull-color laser beam printer was described as an example of the imageforming apparatus, but the present invention is also applicable tovarious other types of image forming apparatuses, such as full-colorlaser beam printers that are not of the intermediate transferring type,monochrome laser beam printers, copying machines, and facsimiles.

INDUSTRIAL APPLICABILITY

According to a main aspect of the present invention, it is possible toachieve an image forming apparatus and a computer system with whichinformation can be accurately written into developing units havingelements, for example.

Further, according to another main aspect of the present invention, itis possible to achieve a developing unit, an image forming apparatus,and a computer system with which communication with an element can becarried out accurately.

1. An image forming apparatus comprising: an attach/detach section toand from which a developing unit having an element into whichinformation can be written and a developer containing section can beattached and detached; a photoconductor on which a latent image can beformed; a writing member for writing information into said element; andan AC voltage supply section for supplying an AC voltage, wherein:during a period from a start to an end of an image forming process, saidwriting member writes information into said element of the developingunit attached to said attach/detach section when said AC voltage supplysection is not supplying an AC voltage, said image forming apparatusfurther comprises: a moving body provided with a plurality of theattach/detach sections, and an attach/detach opening through which saiddeveloping unit is attached to and detached from said attach/detachsection; in a state in which said developing unit is positioned at anopposing position where said developing unit is in opposition to saidphotoconductor due to movement of said moving body, said latent imagecan be developed with the developer contained in said developing unit;in a state in which said developing unit is positioned at a detachingposition that is different from said opposing position due to movementof said moving body, said developing unit can be detached from saidattach/detach section via said attach/detach opening; during a periodfrom when said developing unit arrives at said opposing position untilwhen said developing unit arrives at said detaching position due tomovement of said moving body, said writing member writes informationinto said element of said developing unit; and during a period from whensaid developer bearing body provided in the developing unit that hasarrived at said opposing position ends developing said latent imageuntil when said developing unit arrives at said detaching position, saidwriting member writes information into said element of said developingunit.
 2. An image forming apparatus according to claim 1, wherein duringa period from when said developing unit starts moving from said opposingposition until when said developing unit arrives at said detachingposition due to movement of said moving body, said writing member writesinformation into said element of said developing unit.
 3. An imageforming apparatus according to claim 1, wherein if, during the periodfrom when said developing unit starts moving from said opposing positionuntil when said developing unit arrives at said detaching position,another developing unit adjacent to said developing unit on the upstreamside therefrom in a direction of movement of said moving body arrives atsaid opposing position, then said writing member writes information intosaid element of said developing unit during a period until said otherdeveloping unit arrives at said opposing position.
 4. An image formingapparatus comprising: a photoconductor unit attach/detach section to andfrom which a photoconductor unit having an element into whichinformation can be written and a photoconductor can be attached anddetached; a developing device for developing a latent image formed onsaid photoconductor; a writing member for writing information into saidelement; and an AC voltage supply section for supplying an AC voltage,wherein: during a period from a start to an end of an image formingprocess, said writing member writes information into said element of thephotoconductor unit attached to said photoconductor unit attach/detachsection when said AC voltage supply section is not supplying an ACvoltage; said developing device is a developing unit that is provided asa unit; said image forming apparatus further comprises: a moving bodyprovided with a plurality of developing unit attach/detach sections toand from which said developing unit can be attached and detached, and anattach/detach opening through which said developing unit is attached toand detached from said developing unit attach/detach section; in a statein which said developing unit is positioned at an opposing positionwhere said developing unit is in opposition to said photoconductor dueto movement of said moving body, the latent image on said photoconductorcan be developed with the developer contained in said developing unit;in a state in which said developing unit is positioned at a detachingposition that is different from said opposing position due to movementof said moving body, said developing unit can be detached from saiddeveloping unit attach/detach section via said attach/detach opening;during a period from when said developing unit arrives at said opposingposition until when said developing unit arrives at said detachingposition due to movement of said moving body, said writing member writesinformation into said element of said photoconductor unit; and during aperiod from when said developer bearing body provided in the developingunit that has arrived at said opposing position ends developing saidlatent image until when said developing unit arrives at said detachingposition, said writing member writes information into said element ofsaid photoconductor unit.
 5. An image forming apparatus according toclaim 4, wherein during a period from when said developing unit startsmoving from said opposing position until when said developing unitarrives at said detaching position due to movement of said moving body,said writing member writes information into said element of saidphotoconductor unit.
 6. An image forming apparatus according to claim 4,wherein if, during the period from when said developing unit startsmoving from said opposing position until when said developing unitarrives at said detaching position, another developing unit adjacent tosaid developing unit on the upstream side therefrom in a direction ofmovement of said moving body arrives at said opposing position, thensaid writing member writes information into said element of saidphotoconductor unit during a period until said other developing unitarrives at said opposing position.
 7. A computer system comprising: acomputer unit; and an image forming apparatus connected to said computerunit, said image forming apparatus comprising: an attach/detach sectionto and from which a developing unit having an element into whichinformation can be written and a developer bearing body can be attachedand detached; a photoconductor on which a latent image can be formed; awriting member for writing information into said element; and an ACvoltage supply section for supplying an AC voltage, wherein: during aperiod from a start to an end of an image forming process, said writingmember writes information into said element of the developing unitattached to said attach/detach section when said AC voltage supplysection is not supplying an AC voltage; said image forming apparatusfurther comprises: a moving body provided with a plurality of theattach/detach sections, and an attach/detach opening through which saiddeveloping unit is attached to and detached from said attach/detachsection; in a state in which said developing unit is positioned at anopposing position where said developing unit is in opposition to saidphotoconductor due to movement of said moving body, said latent imagecan be developed with the developer contained in said developing unit;in a state in which said developing unit is positioned at a detachingposition that is different from said opposing position due to movementof said moving body, said developing unit can be detached from saidattach/detach section via said attach/detach opening; during a periodfrom when said developing unit arrives at said opposing position untilwhen said developing unit arrives at said detaching position due tomovement of said moving body, said writing member writes informationinto said element of said developing unit; and during a period from whensaid developer bearing body provided in the developing unit that hasarrived at said opposing position ends developing said latent imageuntil when said developing unit arrives at said detaching position, saidwriting member writes information into said element of said developingunit.
 8. A computer system comprising: a computer unit; and an imageforming apparatus connected to said computer unit, said image formingapparatus comprising: a photoconductor unit attach/detach section to andfrom which a photoconductor unit having an element into whichinformation can be written and a photoconductor can be attached anddetached; a developing device for developing a latent image formed onsaid photoconductor; a writing member; for writing information into saidelement; and an AC voltage supply section for supplying an AC voltage,wherein: during a period from a start to an end of an image formingprocess, said writing member writes information into said element of thephotoconductor unit attached to said photoconductor unit attach/detachsection when said AC voltage supply section is not supplying an ACvoltage; said developing device is a developing unit that is provided asa unit; said image forming apparatus further comprises: a moving bodyprovided with a plurality of developing unit attach/detach sections toand from which said developing unit can be attached and detached, and anattach/detach opening through which said developing unit is attached toand detached from said developing unit attach/detach section; in a statein which said developing unit is positioned at an opposing positionwhere said developing unit is in opposition to said photoconductor dueto movement of said moving body, the latent image on said photoconductorcan be developed with the developer contained in said developing unit;in a state in which said developing unit is positioned at a detachingposition that is different from said opposing position due to movementof said moving body, said developing unit can be detached from saiddeveloping unit attach/detach section via said attach/detach opening;during a period from when said developing unit arrives at said opposingposition until when said developing unit arrives at said detachingposition due to movement of said moving body, said writing member writesinformation into said element of said photoconductor unit; and during aperiod from when said developer bearing body provided in the developingunit that has arrived at said opposing position ends developing saidlatent image until when said developing unit arrives at said detachingposition, said writing member writes information into said element ofsaid photoconductor unit.